JP2004231757A - Composition for insulating film, insulating film, and method for forming insulating film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composition which is used for forming an insulating film, can form a cured insulating film at about 120°C or lower, gives the cured insulating film excellent in adhesion to a substrate or a sealing material and having an improved tin-plating resistance with a tin invasion of 35 μm or less, and is suitable as a printing ink or a coating varnish for forming an insulating film for electric and electronic parts, etc. <P>SOLUTION: The composition for the insulating film contains (a) 100 pts.wt. organic-solvent-soluble resin having epoxy-reactive groups and a polysiloxane backbone, (b) 1-50 pts.wt. epoxy compound, and (c) an organic solvent. A cured insulating film prepared by heat treating the composition is characterized in that both the glass transition temperature derived from the organic-solvent-soluble resin component having epoxy-reactive groups and a polysiloxane backbone and the glass transition temperature derived from the epoxy compound component are 160°C or lower. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

（式中、Ｒ_１は２価の炭化水素基又は芳香族基を示し、Ｒ_２は独立に１価の炭素水素基又は芳香族基を示し、ｎ１は３〜５０の整数を示す。）
また、エポキシ化合物のエポキシ当量が８００を超え且つ４０００未満であることに関する。
また、本発明は、絶縁膜用組成物が、さらに、（ｄ）硬化促進剤を含有すること、及び、前記硬化促進剤が３級アミン類であることに関する。
また、本発明は、絶縁膜用組成物が、さらに、（ｅ）微細フィラーを２０〜１５０重量部含有すること、及び、前記微細なフィラーが、少なくとも微粉状シリカ、タルク、マイカ、又は、硫酸バリウムのいずれか一つを含んでいることに関する。
更に、本発明は、前記のいずれかの絶縁膜用組成物を加熱処理して得られる硬化絶縁膜、及び、前記のいずれかの絶縁膜用組成物を基材に塗布後、５０℃〜２１０℃で加熱処理して硬化絶縁膜を形成する方法に関する。
【００１０】
【発明の実施の形態】
本発明において、ガラス転移温度は、固体動的粘弾性測定装置によって測定された。固体動的粘弾性測定装置では、各温度において一定周波数の正弦的変形を試料に与え、試料に発生する力を検出し弾性率を求める。ガラス転移とは樹脂中の特定セグメントのミクロブラウン運動が凍結あるいは開放される温度であり、固体動的粘弾性測定装置によって得られる貯蔵弾性率および損失弾性率の温度分散曲線において、それぞれ変曲点およびピークをもたらす。更に、損失弾性率と貯蔵弾性率の比である損失正接の温度分散曲線において、ガラス転移温度はピークとして現われる。本発明において、ガラス転移温度は、前述の損失正接の温度分散曲線におけるピークを示す温度として求めた。
【００１１】
エポキシ基との反応性を有し且つポリシロキサン骨格を含有した樹脂を主成分とし、これにエポキシ化合物を加えた組成物は、加熱処理による架橋反応によって硬化絶縁膜を形成することができる。しかし、この硬化絶縁膜は、主成分を構成する樹脂に含有されたポリシロキサン骨格がエポキシ樹脂などの有機材料に対して密着性が低いので、ある種の封止材料に対して密着性が劣ると考えられ、また、エポキシ化合物は、少量成分であり、加熱処理されて硬化絶縁膜が形成されたときには架橋構造になっているから、封止材料との密着性向上に対して有効な効果を発揮し得ないと考えられた。
【００１２】
本発明の絶縁膜用組成物は、加熱処理して硬化絶縁膜を形成したとき、その硬化絶縁膜が、エポキシ基との反応性を有し且つポリシロキサン骨格を含有した樹脂成分（セグメント）に由来したガラス転移温度及びエポキシ化合物成分（セグメント）に由来したガラス転移温度が１６０℃以下になるように構成することによって、封止材料との密着性が改良できたことを一つの特徴とするものである。
【００１３】
硬化絶縁膜と封止材料との密着性について具体的に説明する。通常、硬化絶縁膜が形成された後で，その硬化絶縁膜と接して液状の封止材料が塗布などによって配置され、加熱処理によって封止材料が硬化される。封止材料を硬化するための加熱処理温度は通常１６０℃程度である。硬化絶縁膜に含まれる樹脂成分が１６０℃以下のガラス転移温度を持つことによって、封止材料を硬化させる加熱処理工程で、硬化絶縁膜に含有されるガラス転移温度が１６０℃以下の樹脂成分（セグメント）は運動性が増して、封止材料との界面で封止材料（完全に硬化する前なので運動性が高い）とより緊密な化学的又は物理的相互作用が可能になる。本発明において、１６０℃以下のガラス転移温度を示す硬化絶縁膜中の樹脂成分（セグメント）は、潜在的に封止材料と緊密な化学的又は物理的相互作用を持ち得るものである必要があり、好ましくは、エポキシ基との反応性を有する基を有し且つポリシロキサン骨格を含有してなる樹脂成分（セグメント）及びエポキシ化合物成分（セグメント）である。
【００１４】
本発明において、エポキシ基と反応性を有し且つポリシロキサン骨格を含有した樹脂成分（セグメント）のガラス転移温度は、ポリシロキサン骨格の含有量によって変化する。ポリシロキサン骨格の含有量が少ないと、例えばポリイミドシロキサンの場合には、イミド環を形成した芳香族テトラカルボン酸成分や芳香族ジアミン成分などの芳香族鎖成分の割合が相対的に増えるので、ガラス転移温度が１６０℃を越えてしまうことがある。エポキシ基との反応性を有する基を有し且つポリシロキサン骨格を含有してなる有機溶剤可溶性樹脂は、ポリシロキサン骨格を３０重量％以上、好ましくは４０重量％以上、更に好ましくは５０重量％以上含有することが好適である。
【００１５】
ポリシロキサン骨格の含有量を増すことによって、エポキシ基と反応性を有し且つポリシロキサン骨格を含有した樹脂成分（セグメント）のガラス転移温度は、１６０℃以下、更に５０℃以下、特に室温以下になる。ガラス転移温度を室温以下にすると、得られる硬化絶縁膜が室温において柔軟性を持つので特に好適である。
また、前述のようにして、エポキシ基と反応性を有し且つポリシロキサン骨格を含有した樹脂成分（セグメント）のガラス転移温度を下げた時には、エポキシ基との反応性を有し且つポリシロキサン骨格を含有した樹脂成分と、エポキシ化合物成分とに由来したガラス転移温度のうち、最高のガラス転移温度を示す樹脂成分（セグメント）は、エポキシ化合物成分（セグメント）になる。
【００１６】
本発明において、硬化絶縁膜がエポキシ化合物成分（セグメント）に由来したガラス転移温度を１６０℃以下に有するように調整するためには、絶縁硬化膜のエポキシ化合物が構成する架橋構造が蜜になり過ぎないような構成が重要であり、特にエポキシ化合物をエポキシ当量が比較的大きなもの、すなわち、エポキシ当量が８００を超えたものにすることが好適である。絶縁硬化膜のエポキシ化合物が構成する架橋構造が蜜になると、エポキシ化合物成分に由来するガラス転移温度が１６０℃を超える。
【００１７】
本発明において、前記硬化絶縁膜のエポキシ基との反応性を有する基を有し且つポリシロキサン骨格を含有してなる樹脂成分に由来したガラス転移温度及びエポキシ化合物成分に由来したガラス転移温度が、１６０℃以下、好ましくは１４０℃以下、更に好ましくは１３０℃以下であることが好適である。また、これらの成分（セグメント）のガラス転移が１６０℃以下で完了することが特に好適である。ガラス転移が１６０℃以下で完了するとは、前述の損失正接の温度分散曲線におけるピーク全体が１６０℃以下の範囲内になることを意味する。
【００１８】
尚、エポキシ基との反応性を有する基を有し且つポリシロキサン骨格を含有してなる樹脂成分やエポキシ化合物成分は、それらに由来したガラス転移温度を単数又は複数有する。複数のガラス転移温度を有するのは、エポキシ基との反応性を有する基を有し且つポリシロキサン骨格を含有してなる樹脂成分やエポキシ化合物成分が夫々複数の成分（セグメント）から構成されている時であるが、本発明においては、複数のガラス転移温度が全て１６０℃以下であることが好適である。
また、本発明において、エポキシ基との反応性を有する基を有し且つポリシロキサン骨格を含有してなる樹脂成分及びエポキシ化合物成分に由来したガラス転移温度の下限は特に限定されるものではないが、通常は、ポリシロキサン骨格に由来した−１５０℃程度以上特に−１００℃程度の最も低いガラス転移温度を有する。
【００１９】
本発明において、エポキシ基との反応性を有する基を有し且つポリシロキサン骨格を含有してなる有機溶剤可溶性樹脂とは、分子中に、芳香族ジカルボン酸無水物基、芳香族ジカルボン酸ハーフエステル基、カルボン酸基、水酸基及びアミド基などの、エポキシ基と常温では実質的な硬化反応がおこらず、例えば８０℃以上の比較的高温において硬化反応がおこり得る基を有しており、且つ、主鎖にポリシロキサン骨格を含有した樹脂である。好ましくは、耐熱性などを改良するために、前記主鎖はフレキシブルなポリシロキサン骨格とベンゼン環やイミド環などのリジッドなセグメントとを含んで構成されたものである。
本発明において、エポキシ基との反応性を有する基を有し且つポリシロキサン骨格を含有してなる有機溶剤可溶性樹脂は、限定するものではないが、以下に示すようなポリイミドシロキサンが特に好適である。以下、ポリイミドシロキサンを例に挙げて本発明を説明する。
【００２０】
本発明におけるエポキシ基との反応性を有する基を有し且つポリシロキサン骨格を含有してなる有機溶剤可溶性樹脂として好適なポリイミドシロキサンは、好ましくは、テトラカルボン酸成分と、ジアミノポリシロキサン４５〜９５モル％、極性基を有する芳香族ジアミン０．５〜４０モル％、及び、前記ジアミノポリシロキサン及び前記極性基を有する芳香族ジアミン以外のジアミン０〜５４．５モル％とからなるジアミン成分とを、略等モル好ましくはジアミン成分１モルに対してテトラカルボン酸成分が１．０〜１．２モル程度の割合で用いて有機溶媒中で反応して得ることができる。テトラカルボン酸成分が前記より多すぎると得られるポリイミドシロキサン絶縁膜用組成物の印刷特性が低下するので好ましくない。
【００２１】
ポリイミドシロキサンのテトラカルボン酸成分としては、具体的には、２，３，３’，４’−ビフェニルテトラカルボン酸、３，３’，４，４’−ビフェニルテトラカルボン酸、３，３’，４，４’−ジフェニルエ−テルテトラカルボン酸、３，３’，４，４’−ジフェニルスルホンテトラカルボン酸、３，３’，４，４’−ベンゾフェノンテトラカルボン酸、２，２−ビス（３，４−ベンゼンジカルボン酸）ヘキサフルオロプロパン、ピロメリット酸、１，４−ビス（３，４−ベンゼンジカルボン酸）ベンゼン、２，２−ビス〔４−（３，４−フェノキシジカルボン酸）フェニル〕プロパン、２，３，６，７−ナフタレンテトラカルボン酸、１，２，５，６−ナフタレンテトラカルボン酸、１，２，４，５−ナフタレンテトラカルボン酸、１，４，５，８−ナフタレンテトラカルボン酸、１，１−ビス（２，３−ジカルボキシフェニル）エタンなどの芳香族テトラカルボン酸、又は、それらの酸二無水物や低級アルコ−ルのエステル化物、及び、シクロペンタンテトラカルボン酸、１，２，４，５−シクロヘキサンテトラカルボン酸、３−メチル−４−シクロヘキセン−１，２，４，５−テトラカルボン酸などの脂環族系テトラカルボン酸、又は、それらの酸二無水物や低級アルコ−ルのエステル化物を好適に挙げることができる。これらのなかでも特に、２，３，３’，４’−ビフェニルテトラカルボン酸、及び、３，３’，４，４’−ジフェニルエ−テルテトラカルボン酸、又は、それらの酸二無水物や低級アルコ−ルのエステル化物は、ポリイミドシロキサンとしたときの有機溶媒に対する溶解性が優れているので好適である。
また、本発明において、ポリイミドシロキサンのテトラカルボン酸成分中に、前記で例示したような芳香族テトラカルボン酸成分を８０モル％以上特に８５％〜１００％含有することが好ましい。
【００２２】
本発明におけるポリイミドシロキサンのテトラカルボン酸成分は、ジアミンと反応させることが容易なテトラカルボン酸二無水物を用いることが好ましい。
また、テトラカルボン酸二無水物の使用量がジアミンに対して１．０５倍モル以上で未反応無水環が残存するような場合には、そのままでもよいが、エステル化剤で開環ハーフエステル化してもよい。エステル化剤であるアルコール類の使用量は、過剰なテトラカルボン酸二無水物の１．１〜２０倍当量、特に、１．５〜５倍当量であることが好ましい。アルコール類の割合が少ないと、未反応の無水環が残って、組成物での貯蔵安定性が劣るものとなり、過剰のアルコール類は貧溶媒となって不溶分が析出したり固形分濃度を低くすることになって印刷による塗膜の形成が容易でなくなるので好ましくない。
エステル化剤を用いた場合は、反応溶液をそのまま用いても構わないが、過剰のアルコール類を加熱や減圧留去して使用することもできる。
【００２３】
本発明において、ポリイミドシロキサンのジアミン成分は、下記一般式（１）で示されるジアミノポリシロキサン４５〜９５モル％、極性基を有する芳香族ジアミン０．５〜４０モル％、及び、前記ジアミノポリシロキサン及び前記極性基を有する芳香族ジアミン以外のジアミン０〜５４．５モル％（通常、０〜３０モル％）の割合で使用されることが特に好ましい。いずれかの成分が多すぎたり、少なすぎたりしてこれらの範囲をはずれると得られるポリイミドシロキサンの有機溶媒に対する溶解性が低下したり、他の有機化合物との相溶性が悪くなったり、配線基板上に形成した絶縁膜の曲率半径が小さくなり耐屈曲性が低下したり、基材との密着性および耐熱性が低下するので好ましくない。
【００２４】
本発明におけるポリイミドシロキサンのジアミン成分を構成する下記一般式（１）で示されるジアミノポリシロキサンは、好ましくは、前記式中Ｒ_１は炭素数１〜６の２価の炭化水素基又はフェニレン基、特にプロピレン基であり、前記式中Ｒ２は独立に炭素数１〜５のアルキル基又はフェニル基であり、前記式中ｎ１は３〜５０、特に３〜２０である。ｎ１が３未満では得られる絶縁膜の耐屈曲性が悪くなるので好ましくなく、又、ｎ１が５０を超えるとテトラカルボン酸成分との反応性が低下して得られるポリイミドシロキサンの分子量が低くなったり、ポリイミドシロキサンの有機溶剤に対する溶解性が低くなったり、組成物における他の有機成分との相溶性が悪くなったり、得られる絶縁膜の耐溶剤性が低くなったりするので前記程度のものが好適である。尚、ジアミノポリシロキサンが２種以上の混合物からなる場合は、ｎ１はアミノ当量から計算される。
【化３】

（式中、Ｒ_１は２価の炭化水素基又は芳香族基を示し、Ｒ_２は独立に１価の炭素水素基又は芳香族基を示し、ｎ１は３〜５０の整数を示す。）
【００２５】
前記ジアミノポリシロキサンの具体的化合物の例としては、α，ω−ビス（２−アミノエチル）ポリジメチルシロキサン、α，ω−ビス（３−アミノプロピル）ポリジメチルシロキサン、α，ω−ビス（４−アミノフェニル）ポリジメチルシロキサン、α，ω−ビス（４−アミノ−３−メチルフェニル）ポリジメチルシロキサン、α，ω−ビス（３−アミノプロピル）ポリジフェニルシロキサン、α，ω−ビス（４−アミノブチル）ポリジメチルシロキサンなどが挙げられる。
【００２６】
この発明におけるポリイミドシロキサンのジアミン成分を構成する極性基を有する芳香族ジアミンは、分子中にエポキシ基との反応性を有する極性基を有する芳香族ジアミンであり、好ましくは、下記一般式（２）で示されるジアミンである。
【化４】

（式中、Ｘ及びＹは、それぞれ独立に直接結合、ＣＨ_２、Ｃ（ＣＨ_３）_２、Ｃ（ＣＦ_３）_２、Ｏ、ベンゼン環、ＳＯ_２を示し、ｒ１はＣＯＯＨ又はＯＨを示し、ｎ２は１又は２であり、ｎ３、ｎ４はそれぞれ独立に０、１又は２、好ましくは０又は１であり、ｎ３及びｎ４の少なくとも一方は１又は２である。）
【００２７】
前記一般式（２）で示されるジアミン化合物としては、２，４−ジアミノフェノ−ルなどのジアミノフェノ−ル化合物類、３，３’−ジアミノ−４，４’−ジハイドロキシビフェニル、４，４’−ジアミノ−３，３’−ジハイドロキシビフェニル、４，４’−ジアミノ−２，２’−ジハイドロキシビフェニル、４，４’−ジアミノ−２，２’，５，５’−テトラハイドロキシビフェニルなどのヒドロキシビフェニル化合物類、３，３’−ジアミノ−４，４’−ジハイドロキシジフェニルメタン、４，４’−ジアミノ−３，３’−ジハイドロキシジフェニルメタン、４，４’−ジアミノ−２，２’−ジハイドロキシジフェニルメタン、２，２−ビス〔３−アミノ−４−ハイドロキシフェニル〕プロパン、２，２−ビス〔４−アミノ−３−ハイドロキシフェニル〕プロパン、２，２−ビス〔３−アミノ−４−ハイドロキシフェニル〕ヘキサフルオロプロパン、４，４’−ジアミノ−２，２’，５，５’−テトラハイドロキシジフェニルメタンなどのヒドロキシジフェニルアルカン化合物類、３，３’−ジアミノ−４，４’−ジハイドロキシジフェニルエ−テル、４，４’−ジアミノ−３，３’−ジハイドロキシジフェニルエ−テル、４，４’−ジアミノ−２，２’−ジハイドロキシジフェニルエ−テル、４，４’−ジアミノ−２，２’，５，５’−テトラハイドロキシジフェニルエ−テルなどのヒドロキシジフェニルエ−テル化合物類、３，３’−ジアミノ−４，４’−ジハイドロキシジフェニルスルホン、４，４’−ジアミノ−３，３’−ジハイドロキシジフェニルスルホン、４，４’−ジアミノ−２，２’−ジハイドロキシジフェニルスルホン、４，４’−ジアミノ−２，２’，５，５’−テトラハイドロキシジフェニルスルホンなどのヒドロキシジフェニルスルホン化合物類、２，２−ビス〔４−（４−アミノ−３−ハイドロキシフェノキシ）フェニル〕プロパンなどのビス（ハイドロキシフェニキシフェニル）アルカン化合物類、４，４’−ビス（４−アミノ−３−ハイドロキシフェノキシ）ビフェニルなどのビス（ハイドロキシフェノキシ）ビフェニル化合物類、２，２−ビス〔４−（４−アミノ−３−ハイドロキシフェノキシ）フェニル〕スルホンなどのビス（ハイドロキシフェニキシフェニル）スルホン化合物類などのＯＨ基を有するジアミン化合物を挙げることができる。
【００２８】
更に、前記の一般式（２）で示されるジアミン化合物としては、３，５−ジアミノ安息香酸、２，４−ジアミノ安息香酸などのベンゼンカルボン酸類、３，３’−ジアミノ−４，４’−ジカルボキシビフェニル、４，４’−ジアミノ−３，３’−ジカルボキシビフェニル、４，４’−ジアミノ−２，２’−ジカルボキシビフェニル、４，４’−ジアミノ−２，２’，５，５’−テトラカルボキシビフェニルなどのカルボキシビフェニル化合物類、３，３’−ジアミノ−４，４’−ジカルボキシジフェニルメタン、４，４’−ジアミノ−３，３’−ジカルボキシジフェニルメタン、４，４’−ジアミノ−２，２’−ジカルボキシジフェニルメタン、２，２−ビス〔３−アミノ−４−カルボキシフェニル〕プロパン、２，２−ビス〔４−アミノ−３−カルボキシフェニル〕プロパン、２，２−ビス〔３−アミノ−４−カルボキシフェニル〕ヘキサフルオロプロパン、４，４’−ジアミノ−２，２’，５，５’−テトラカルボキシビフェニルなどのカルボキシジフェニルアルカン化合物類、３，３’−ジアミノ−４，４’−ジカルボキシジフェニルエ−テル、４，４’−ジアミノ−３，３’−ジカルボキシジフェニルエ−テル、４，４’−ジアミノ−２，２’−ジカルボキシジフェニルエ−テル、４，４’−ジアミノ−２，２’，５，５’−テトラカルボキシジフェニルエ−テルなどのカルボキシジフェニルエ−テル化合物類、３，３’−ジアミノ−４，４’−ジカルボキシジフェニルスルホン、４，４’−ジアミノ−３，３’−ジカルボキシジフェニルスルホン、４，４’−ジアミノ−２，２’，５，５’−テトラカルボキシジフェニルスルホンなどのカルボキシジフェニルスルホン化合物類、２，２−ビス〔４−（４−アミノ−３−カルボキシフェノキシ）フェニル〕プロパンなどのビス（カルボキシフェノキシフェニル）アルカン化合物類、４，４’−ビス（４−アミノ−３−カルボキシフェノキシ）ビフェニルなどのビス（カルボキシフェノキシ）ビフェニル化合物類、２，２−ビス〔４−（４−アミノ−３−カルボキシフェノキシ）フェニル〕スルホンなどのビス（カルボキシフェノキシフェニル）スルホン化合物類などのＣＯＯＨ基を有するジアミン化合物を挙げることができる。
【００２９】
本発明におけるポリイミドシロキサンのジアミン成分を構成する前記ジアミノポリシロキサン及び前記極性基を有する芳香族ジアミン以外のジアミンは、特に限定されるものではないが、下記一般式（３）で示される芳香族ジアミンが好適である。
【化５】

（式中、Ｘ及びＹは、それぞれ独立に直接結合、ＣＨ_２、Ｃ（ＣＨ_３）_２、Ｃ（ＣＦ_３）_２、Ｏ、ベンゼン環、ＳＯ_２を示し、ｎ５は１又は２である。）
【００３０】
前記一般式（３）で示される芳香族ジアミンは、具体的には、１，４−ジアミノベンゼン、１，３−ジアミノベンゼン、２，４−ジアミノトルエン、１，４−ジアミノ−２，５−ジハロゲノベンゼンなどのベンゼン１個を含むジアミン類、ビス（４−アミノフェニル）エ−テル、ビス（３−アミノフェニル）エ−テル、ビス（４−アミノフェニル）スルホン、ビス（３−アミノフェニル）スルホン、ビス（４−アミノフェニル）メタン、ビス（３−アミノフェニル）メタン、ビス（４−アミノフェニル）スルフィド、ビス（３−アミノフェニル）スルフィド、２，２−ビス（４−アミノフェニル）プロパン、２，２−ビス（３−アミノフェニル）プロパン、２，２−ビス（４−アミノフェニル）ヘキサフルオロプロパン、ｏ−ジアニシジン、ｏ−トリジン、トリジンスルホン酸類などのベンゼン２個を含むジアミン類、１，４−ビス（４−アミノフェノキシ）ベンゼン、１，４−ビス（３−アミノフェノキシ）ベンゼン、１，４−ビス（４−アミノフェニル）ベンゼン、１，４−ビス（３−アミノフェニル）ベンゼン、α，α’−ビス（４−アミノフェニル）−１，４−ジイソプロピルベンゼン、α，α’−ビス（４−アミノフェニル）−１，３−ジイソプロピルベンゼンなどのベンゼン３個を含むジアミン類、２，２−ビス〔４−（４−アミノフェノキシ）フェニル〕プロパン、２，２−ビス〔４−（４−アミノフェノキシ）フェニル〕ヘキサフルオロプロパン、２，２−ビス〔４−（４−アミノフェノキシ）フェニル〕スルホン、４，４’−（４−アミノフェノキシ）ビフェニル、９，９−ビス（４−アミノフェニル）フルオレン、５，１０−ビス（４−アミノフェニル）アントラセンなどのベンゼン４個以上を含むジアミン類などのジアミン化合物が挙げられる。
また、ヘキサメチレンジアミン、ジアミノドデカンなど脂肪族ジアミン化合物を上記ジアミンと共に使用することができる。
【００３１】
本発明におけるポリイミドシロキサンは、特に限定するものではないが、例えば、次の方法で得ることができる。
（１）テトラカルボン酸成分とジアミン成分とを略等モル使用し、有機極性溶媒中で連続的に１５〜２５０℃で重合及びイミド化させてポリイミドシロキサンを得る方法。
（２）テトラカルボン酸成分とジアミン成分とをそれぞれ分けて、まず過剰量のテトラカルボン酸成分とアミン成分（例えばジアミノポリシロキサン）とを有機極性溶媒中１５〜２５０℃で重合及びイミド化させて平均重合度１〜１０程度の末端に酸無水物基（又は、酸、そのエステル化物）を有するイミドシロキサンオリゴマーを調製し、別にテトラカルボン酸成分と過剰量のジアミン成分とを有機極性溶媒中１５〜２５０℃で重合及びイミド化させて平均重合度１〜１０程度の末端にアミノ基を有するイミドオリゴマーを調製し、次いでこの両者を、酸成分とジアミン成分とが略等モルになるように混合して１５〜６０℃で反応させて、さらに１３０〜２５０℃に昇温して反応させて、ブロックタイプのポリイミドシロキサンを得る方法。
（３）テトラカルボン酸成分とジアミン成分とを略等モル使用し、有機極性溶媒中でまず２０〜８０℃で重合させてポリアミック酸を得た後に、そのポリアミック酸をイミド化してポリイミドシロキサンを得る方法。
【００３２】
上述の方法でポリイミドシロキサンを得る際に使用される有機極性溶媒としては、含窒素系溶媒、例えばＮ，Ｎ−ジメチルアセトアミド、Ｎ，Ｎ−ジエチルアセトアミド、Ｎ，Ｎ−ジメチルホルムアミド、Ｎ，Ｎ−ジエチルホルムアミド、Ｎ−メチル−２−ピロリドン、１，３−ジメチル−２−イミダゾリジノン、Ｎ−メチルカプロラクタムなど、硫黄原子を含有する溶媒、例えばジメチルスルホキシド、ジエチルスルホキシド、ジメチルスルホン、ジエチルスルホン、ヘキサメチルスルホルアミドなどフェノール系溶媒、例えばクレゾール、フェノール、キシレノールなど、ジグライム系溶媒、例えばジエチレングリコールジメチルエーテル（ジグライム）、トリエチレングリコールジメチルエーテル（トリグライム）、テトラグライムなど、酸素原子を分子内に有する溶媒、例えばアセトン、メタノール、エタノール、エチレングリコール、ジオキサン、テトラヒドロフランなど、その他ピリジン、テトラメチル尿素などを挙げることができる。また必要に応じてベンゼン、トルエン、キシレンなどの芳香族炭化水素系溶媒やソルベントナフサ、ベンゾニトリルなど他の有機溶媒を併用してもよい。
【００３３】
本発明において、ポリイミドシロキサンは、前記（１）〜（３）などいずれの方法で得られたものを使用してもよいが、有機溶媒に少なくとも３重量％以上、好ましくは５〜６０重量％、特に５〜５０％程度の高濃度で溶解させることができるもので、２５℃の溶液粘度（Ｅ型回転粘度計）が１〜１００００ポイズ、特に１〜１００ポイズであることが好ましい。
本発明において、ポリイミドシロキサンはより高分子量のものが好ましく更にイミド化率が高いものが好ましい。分子量の目安としての対数粘度（測定濃度：０．５ｇ ／１００ミリリットル、溶媒：Ｎ−メチル−２−ピロリドン、測定温度：３０℃）は、０．１５以上、特に０．１６〜２のものが、硬化後の膜の強度、伸度などの機械的物性の点から好ましい。また、赤外吸収スペクトルから求められるイミド化率は、９０％以上特に９５％以上更に実質的に１００％のものが好ましい。
【００３４】
本発明のポリイミドシロキサン絶縁膜用組成物を構成するエポキシ化合物は、複数のエポキシ基を有する化合物であって、エポキシ当量が８００を超え特に８５０以上且つ４０００未満特に３０００以下のものであって、常温で液状又は固体状のエポキシ樹脂が好適である。エポキシ化合物のエポキシ当量が８００以下では、硬化絶縁膜としたときのガラス転移温度を１６０℃以下にすることが容易ではなくなり、封止材料に対する密着性が劣る。また、エポキシ化合物のエポキシ当量が４０００以上では、硬化絶縁膜としたときのガラス転移温度を１６０℃以下にすることは可能であるが、得られる絶縁膜用組成物が高粘度化し易く取り扱いが容易ではなくなる。
具体的には、例えば、ジャパンエポキシレジン株式会社製 エピコート１０５５、エピコート１００４、エピコート１００４ＡＦ、エピコート１００７、エピコート１００９、エピコート１０１０、大日本インキ化学工業株式会社製 ＥＰＩＣＬＯＮ４０５０、ＥＰＩＣＬＯＮ７０５０、ＡＭ−０４０−Ｐ、ＨＭ０９１、ＨＭ−１０１等のビスフェノールＡ型エポキシ樹脂、ジャパンエポキシレジン株式会社製 エピコート４００４Ｐ、エピコート４００７Ｐ、エピコート４１１０等のビスフェノールＦ型エポキシ樹脂、宇部興産株式会社製のハイカーＥＴＢＮ１３００×４０、及び、ナガセケムテック株式会社製のデナレックスＲ−４５ＥＰＴなどを好適に挙げることができる。
【００３５】
本発明において、エポキシ化合物の使用量は、ポリイミドシロキサン１００重量部に対して、１〜５０重量部、好ましくは２〜３０重量部である。使用量が多すぎるとゲル化し易くなったり密着性が低下し、少なすぎると加熱処理後の硬化絶縁の耐熱性や耐薬品性悪くなるので上記範囲が好ましい。
【００３６】
本発明において、エポキシ化合物と共にヒドラジン類、イミダゾール類、３級アミン類などのエポキシ化合物の硬化反応を促進する硬化促進剤を添加することが好ましい。
特に、３級アミン類を硬化促進剤として添加すると、その絶縁膜用組成物は、基材に塗布後１２０℃程度以下の低温で加熱処理することによって硬化絶縁膜（保護膜）を容易に得ることができるので極めて好適である。本発明において好適に用いることができる３級アミン類としては、具体的には、１，８−ジアザビシクロ［５．４．０］−７−ウンデセン、Ｎ，Ｎ−ジメチルベンジルアミン、Ｎ，Ｎ，Ｎ’，Ｎ’−テトラメチルヘキサンジアミン、トリエチレンジアミン、２−ジメチルアミノメチルフェノール、２，４，６−トリス（ジメチルアミノメチル）フェノール、ジモルホリノジエチルエーテル、１，４−ジメチルピペラジン、シクロヘキシルジメチルアミンなどを挙げることができる。
また、３級アミン類などの硬化促進剤は、ポリイミドシロキサン１００重量部に対して、０．５〜２０重量部好ましくは１〜１０重量部使用するのが好適である。使用量が２０重量部を超えると耐溶剤性や電気的性質が悪くなり、少なすぎると低温での硬化に長時間を要するので上記範囲が好ましい。
【００３７】
本発明のポリイミドシロキサン絶縁膜用組成物を構成する有機溶媒としては、ポリイミドシロキサンを調製するときの反応に使用した有機溶媒をそのまま使用することができるが、好適には、含窒素系溶媒、例えばＮ，Ｎ−ジメチルアセトアミド、Ｎ，Ｎ−ジエチルアセトアミド、Ｎ，Ｎ−ジメチルホルムアミド、Ｎ，Ｎ−ジエチルホルムアミド、Ｎ−メチル−２−ピロリドン、１，３−ジメチル−２−イミダゾリジノン、Ｎ−メチルカプロラクタムなど、含硫黄原子溶媒、例えばジメチルスルホキシド、ジエチルスルホキシド、ジメチルスルホン、ジエチルスルホン、ヘキサメチルスルホルアミドなど、含酸素溶媒、例えばフェノ−ル系溶媒、例えばクレゾ−ル、フェノ−ル、キシレノ−ルなど、ジグライム系溶媒例えばジエチレングリコ−ルジメチルエ−テル（ジグライム）、トリエチレングリコ−ルジメチルエ−テル（トリグライム）、テトラグライムなど、アセトン、アセトフェノン、プロピオフェノン、エチレングリコール、ジオキサン、テトラヒドロフランなどを挙げることができる。特に、Ｎ−メチル−２−ピロリドン、Ｎ，Ｎ−ジメチルスルホキシド、Ｎ，Ｎ−ジメチルホルムアミド、Ｎ，Ｎ−ジエチルホルムアミド、Ｎ，Ｎ−ジメチルアセトアミド、Ｎ，Ｎ−ジエチルアセトアミド、γ−ブチロラクトン、トリエチレングリコ−ルジメチルエ−テル、ジエチレングリコ−ルジメチルエ−テルなどを好適に使用することができる。
【００３８】
更に、本発明の絶縁膜用組成物においては、微細フィラーを含有することが好ましい。微細無機フィラ−としては、どのような形態のものでもよいが、平均粒子径が０．００１〜１５μｍ、特に０．００５〜１０μｍのものが好ましい。この範囲外のものを使用すると得られる塗膜が屈曲したときに亀裂が発生したり、折り曲げ部が白化したりするので好ましくない。微細フィラ−としては、例えば微粉状シリカ、タルク、マイカ、硫酸バリウムなどの微細無機フィラ−や架橋ＮＢＲ微粒子などの微細有機フィラ−を好適に挙げることができる。
【００３９】
微細無機フィラ−の使用量は、エポキシ基との反応性を有する基を有し且つポリシロキサン骨格を含有してなる有機溶剤可溶性樹脂１００重量部に対して、合計で２０〜１５０重量部、好ましくは４０〜１２５重量部である。使用量が、余り多すぎたり、余り少なすぎると塗膜の折り曲げによりクラックが発生したり、印刷性、半田耐熱性、銅箔変色性が影響を受けるので上記範囲が好適である。また、微細無機フィラー、特に微粉状シリカとタルク、マイカあるいは硫酸バリウムの少なくとも１種とを組み合わせて使用し、微紛状シリカをエポキシ基との反応性を有する基を有し且つポリシロキサン骨格を含有してなる有機溶剤可溶性樹脂１００重量部に対して１〜５０重量部、特に５〜４０重量部、タルク、マイカあるいは硫酸バリウムの少なくとも１種を２０〜１３０重量部使用することが、印刷性や得られる硬化絶縁膜の性能を考慮すると特に好ましい。
【００４０】
また、本発明の絶縁膜用組成物においては、有機着色顔料、無機着色顔料を所定量、例えばエポキシ基との反応性を有する基を有し且つポリシロキサン骨格を含有してなる有機溶剤可溶性樹脂１００重量部に対して、０〜１００重量部程度使用することができる。
また、本発明の絶縁膜用組成物においては、消泡剤を所定量、例えばエポキシ基との反応性を有する基を有し且つポリシロキサン骨格を含有してなる有機溶剤可溶性樹脂１００重量部に対して、０．１〜１０重量部程度使用することができる。
【００４１】
本発明の絶縁膜用組成物は、エポキシ基との反応性を有する基を有し且つポリシロキサン骨格を含有してなる樹脂、例えばポリイミドシロキサンと、エポキシ化合物と、微細フィラーと、有機溶媒などとを、所定量混合し、均一に撹拌・混合することによって容易に得ることができる。混合する際に有機溶媒中で混合して溶液組成物にすることができる。有機溶媒に混合させて溶液組成物にするにあたっては、エポキシ基との反応性を有する基を有し且つポリシロキサン骨格を含有してなる樹脂例えばポリイミドシロキサンの重合溶液をそのままでも、又その重合溶液を適当な有機溶媒で希釈したものを使用してもよい。有機溶媒としては、前記樹脂例えばポリイミドシロキサンを得る際に使用できる有機極性溶媒を挙げることができるが、沸点１４０℃以上で２１０℃以下のものを使用することが好ましい。特に沸点１８０℃以上、特に２００℃以上である有機溶媒（例えばメチルトリグライムなど）を使用すると、溶媒の蒸発による散逸が極めて減少するので、又その印刷インクを使用してスクリーン印刷などで印刷を支障なく好適に行うことができるので最適である。有機溶媒は、エポキシ基との反応性を有する基を有し且つポリシロキサン骨格を含有してなる樹脂、例えばポリイミドシロキサン１００重量部に対して６０〜２００重量程度使用する。
【００４２】
本発明の絶縁膜用組成物は、室温（２５℃）で溶液粘度が１００〜６００ポイズであることが作業性や溶液物性、その保護膜特性上などから適当である。
【００４３】
本発明の絶縁膜用組成物は、ＩＣチップなどのチップ部品を実装する電気電子部品の絶縁膜（保護膜）を形成するために用いることができる。
例えば、導電性金属箔で形成された配線パターンを有する絶縁性フィルムのパターン面に、乾燥膜の厚さが３〜６０μｍ程度となるようにスクリ−ン印刷などによって印刷して塗布した後、５０〜１００℃程度の温度で５〜６０分間程度、次いで、１００〜２１０℃程度好適には１２０〜２００℃で５〜１２０分間好適には１０〜６０分間程度の２段階で加熱し乾燥して、好適には弾性率が０．１〜２０ｋｇｆ／ｍｍ^２の絶縁膜を形成することが好ましい。
【００４４】
更に、本発明の絶縁膜用組成物は、５０〜１３０℃程度特に６０〜１２０℃の低温の加熱処理によって硬化させて、前記のような良好な性能を持った絶縁膜を容易に形成することができる。
このために、本発明の絶縁膜用組成物は、実装工程において、１６０℃程度又はそれ以上の比較的高温の加熱処理によって硬化絶縁膜を形成することもできるし、１３０℃以下好ましくは１２０℃程度以下の比較的低温の加熱処理によって硬化絶縁膜を形成することもできる。また、１３０℃以下好ましくは１２０℃程度以下の比較的低温の加熱処理によって硬化絶縁膜を形成したあとで、更に、１６０℃程度又はそれ以上の比較的高温の加熱処理がおこなわれても構わない。
【００４５】
言い換えれば、本発明の絶縁膜用組成物は、例えば絶縁フィルム基材にＩＣチップなどのチップ部品を実装する際に、配線パターンを保護する絶縁膜を形成した後でスズメッキする手順で実装することもできるし、配線パターンを先にスズメッキした後でそれを保護するための絶縁膜を形成する手順で実装することも可能である。
先にスズメッキする手順は、例えば絶縁フィルム基材に実装する場合、以下のようになる。即ち、▲１▼絶縁フィルム基材表面に形成された銅箔の配線パターン表面をスズメッキする。▲２▼絶縁フィルム基材表面の所定部分に、本発明の絶縁膜用組成物を塗布または印刷し、それを１２０℃程度以下の比較的低温で加熱処理して硬化させて絶縁膜（保護膜）を形成する。▲３▼ＩＣチップなどの電子部品を金バンプなどを用いて絶縁膜を形成していない配線パターンのインナーリード部などに実装する。この時、接続部が金スズ共晶を形成するように、短時間だが４００℃程度以上の加熱処理がなされる。▲４▼次いでＩＣチップなどを封止材料などによって保護する。この時に封止材料などを硬化させるために１６０℃程度の温度で加熱処理がおこなわれる。
【００４６】
本発明の絶縁膜用組成物が前述の先にスズメッキする手順で用いられて、電子部品の絶縁膜を形成したときの一例について、概略の断面図を図８に示す。
図８において、例えば２５μｍ厚のポリイミドフィルム１の表面に、例えば１２μｍ厚の銅箔で配線パターン２が形成されており、その表面をメッキされた例えば０．５μｍ厚のスズ層３が覆っている。更にそれらの表面を、インナーリードの接続部分を除いてこの発明の絶縁用組成物からなる絶縁膜４が例えば１０μｍ厚の保護膜を形成している。接続部分では金バンプ５を用いＩＣチップ６が実装され、例えばエポキシ樹脂系の封止材料７によって保護されている。
【００４７】
また、本発明の絶縁膜用組成物は、導電性金属及び絶縁用の各種材料との密着性が良好であり、硬化物は好適な機械的強度や電気絶縁性能を有しているから、電気電子部品の保護膜としてのみならず層間絶縁膜としても好適に使用することができる。更に、本発明の絶縁膜用組成物は、低温圧着が可能でしかも耐熱性の接着剤として好適に使用することもできる。
【００４８】
【実施例】
以下、実施例及び比較例を示し、この発明を説明する。尚、この発明は以下の実施例に限定されるものではない。
【００４９】
各例において測定、評価は次の方法で行った。
（溶液粘度）
Ｅ型粘度計（東京計器社製）を用い、温度２５℃で、回転数１０ｒｐｍにて測定した。
（印刷性の評価）
スクリ−ン印刷可能で、形成された膜にピンホ−ルがなく、端部の流れ出しがない場合を○、スクリ−ン印刷が不可能かまたは膜にピンホ−ルの発生があるかまたは端部の流れ出しがある場合を×で表示した。
【００５０】
（硬化絶縁膜の評価）
硬化絶縁膜の評価は、評価項目によって、以下のように加熱処理された硬化絶縁膜サンプルについておこなった。
すなわち、耐溶剤性、ガラス転移温度及び封止材料との密着性の評価は、実装工程において先にスズメッキが施された導体配線上に絶縁膜用組成物を塗布したときには１２０℃程度以下で加熱硬化することを考慮して、８０℃で３０分次いで１２０℃で１時間加熱処理したサンプルについておこなった。但し、封止材料との密着性の評価は、前記サンプル表面に更に封止材料を滴下して塗布し１６０℃で加熱硬化するから、併せると１２０℃及び１６０℃の２回の加熱処理がされたことになる。
それ以外の硬化絶縁膜の評価は、実装工程において封止材料を硬化するために最終的に１６０℃程度の加熱処理がおこなわれることを考慮して、８０℃で３０分次いで１６０℃で１時間加熱処理したサンプルについておこなった。
【００５１】
耐溶剤性の評価：
厚さがおよそ７５μｍになるように硬化させたシート状サンプル０．５ｇを１００ｍｌのアセトン（２５℃）に３０分間浸漬した後、アセトン可溶分の重量％で示した。
ガラス転移温度：
樹脂成分（セグメント）のガラス転移温度は、基本的には含有するフィラーの影響を受けない。ここでは、フィラーを含まない樹脂成分だけからなる組成物を用いて作成したサンプルについてガラス転移温度を測定した。フィラー含有サンプルを用いると、得られる損失正接（ｔａｎδ）の温度変化を示すチャートにおいてガラス転移温度を示すピークが不明瞭になり易いためである。フィラーを含む組成物を用いて作成したサンプルについて測定しても構わない。
具体的には、厚さ７５μｍのシート状に硬化した試料を幅５ｍｍ、長さ３０ｍｍの短冊状に切り出して、レオメトリックスサイエンティフィック製固体粘弾性アナライザーＲＳＡＩＩを用いて、引張り−圧縮モードで、周波数１０Ｈｚ、窒素気流中、温度ステップ２℃で各設定温度に到達後３０秒後に測定を行ない次の温度に昇温し測定を繰り返し、損失正接（ｔａｎδ）の温度変化を求めた。
具体例で説明すれば、例えば、後述の実施例１の組成物から得られた硬化絶縁膜の損失正接（ｔａｎδ）の温度変化は図１のようになる。この図において、−１００℃、５℃および１１０℃のピークは、それぞれポリイミドシロキサンのポリシロキサン成分、ポリイミドシロキサンの芳香族鎖成分、及びエポキシ化合物成分に由来するガラス転移温度を示している。尚、図１における１３０℃以上で見られる測定点のバラツキは、各成分がそれぞれガラス転移温度を超えた結果、硬化絶縁膜が全体として柔らかくなり測定する弾性率にバラツキが生じるためである。この様なバラツキが生じる状態は、硬化絶縁膜の実質的に全樹脂成分（セグメント）の運動性が増しており、封止材料との界面で封止材料とより緊密な化学的又は物理的相互作用を可能にして密着性を高めると考えられる。一方、この様なバラツキが見られない場合は、ガラス転移温度以上になっても硬化絶縁膜が全体としてはリジッドな状態にあることを示している。
【００５２】
ＩＣ封止材料との密着性の評価：
３５μｍ厚電解銅箔光沢面上に絶縁膜用組成物を３０μｍ厚に塗布し硬化させ、この硬化膜上にＩＣチップ封止材料ＣＥＬ−Ｃ−５０２０（日立化成工業株式会社製）を約１ｍｍ厚、直径０．５ｃｍ程度の円状に滴下して塗布し１６０℃で硬化させサンプルとした。手でサンプルを折り曲げ、封止樹脂のはがれ具合を観察した。硬化絶縁膜で凝集破壊を起こした場合を○、硬化絶縁膜の凝集破壊と硬化絶縁膜／封止材料界面剥離が共存する場合を△、硬化絶縁膜膜／封止材料界面剥離の場合を×で示した。
【００５３】
電気絶縁性（体積抵抗）の測定：
この溶液組成物を用いて厚さ約７５μｍの硬化絶縁膜を形成し、その膜の電気絶縁性（体積抵抗）をＪＩＳ Ｃ−２１０３によって測定した。
引張弾性率の測定：
厚さがおよそ７５μｍになるように硬化させたシート状サンプルを、幅１ｃｍ、長さ１５ｃｍに切り出して試験に用いた。ＡＳＴＭ Ｄ８８２によって測定した。
【００５４】
スズ潜りの測定：
厚さ３５μｍの電解銅箔（三井金属鉱業社製）光沢面上に絶縁膜用組成物を３０μｍ厚に塗布し硬化させたサンプルを、無電解スズメッキ液（シプレイファーイースト社製、ＬＴ−３４）を使用し、温度７０℃で４分間スズメッキし、絶縁膜の端部においてスズが浸入してスズ潜りが起こった部分の幅（端部からの距離）を測定した。
【００５５】
以下の各例で使用したエポキシ樹脂、硬化触媒、フィラーについて説明する。（エポキシ樹脂）
エピコート１００７：ジャパンエポキシレジン社製、エポキシ当量２０００
エピコート１００４：ジャパンエポキシレジン社製、エポキシ当量９００
ハイカーＥＴＢＮ１３００×４０：宇部興産社製、エポキシ当量２７７０、キシレン５０％溶液
エピコート１５７Ｓ７０：ジャパンエポキシレジン社製、エポキシ当量２１０
（硬化触媒）
ＤＢＵ：アルドリッチ社製、１，８‐ジアザビシクロ［５．４．０］‐７‐ウンデセン
キュアゾール２Ｅ４ＭＺ：四国化成工業社製、２−エチル−４−メチルイミダゾール
（微粉状シリカ）
アエロジル５０：日本アエロジル株式会社製、平均粒径：３０ｎｍ
アエロジル１３０：日本アエロジル株式会社製、平均粒径：１６ｎｍ
（硫酸バリウム）
硫酸バリウムＢ−３０：堺化学工業社製、平均粒径０．３μｍ
（タルク）
ミクロエースＰ−３：日本タルク社製、平均粒径１．８μｍ
（マイカ）
ＭＫ−１００：コープケミカル社製、平均粒径２．６μｍ
【００５６】
参考例１（ポリイミドシロキサンの製造）
容量５００ｍｌのガラス製フラスコに、２，３，３’，４’−ビフェニルテトラカルボン酸二無水物５８．８４ｇ（０．２モル）、溶媒のトリグライム（以下、ＴＧと略記することもある。）１２０ｇを仕込み、窒素雰囲気下、１８０℃で加熱撹拌した。α，ω−ビス（３−アミノプロピル）ポリジメチルシロキサン（アミノ当量４５５）１５４．７ｇ（０．１７モル）、ＴＧ７０ｇを加え、１８０℃で６０分間加熱撹拌した。さらにこの反応溶液に４，４’−ジアミノ−３，３’−ジカルボキシフェニルメタン８．５９ｇ（０．０３モル）及びＴＧ２３．４ｇを加え、１８０℃で５時間加熱撹拌した後、濾過を行った。得られたポリイミドシロキサン反応溶液は、ポリマ−固形分濃度５０重量％、ηｉｎｈ０．１８の溶液であった。イミド化率は実質的に１００％であった。
【００５７】
参考例２（ポリイミドシロキサンの製造）
容量５００ｍｌのガラス製フラスコに、２，３，３’，４’−ビフェニルテトラカルボン酸二無水物５８．８４ｇ（０．２モル）、ＴＧ１７０ｇを仕込み、窒素雰囲気下、１８０℃で加熱撹拌した。１００℃付近まで冷却し、α，ω−ビス（３−アミノプロピル）ポリジメチルシロキサン（アミノ当量４５５）１２７．４ｇ（０．１４モル）とＴＧ５０ｇを加え、１８０℃で６０分間加熱撹拌した。さらに、室温付近まで冷却後、この反応溶液に２，２−ビス［４−（４−アミノフェノキシ）フェニル］プロパン１３．５２ｇ（０．０３モル）、３，５ジアミノ安息香酸４．５６ｇ（０．０３モル）及びＴＧ７９ｇを加え、１８０℃で５時間加熱撹拌した後、濾過を行った。得られたポリイミドシロキサン反応溶液は、ポリマ−固形分濃度４０重量％、ηｉｎｈ０．２０の溶液であった。イミド化率は実質的に１００％であった。
【００５８】
実施例１
ガラス製容器に、参考例１で得たポリイミドシロキサン溶液と、ポリイミドシロキサン１００重量部に対してエポキシ樹脂のエピコート１００７を１０重量部、３級アミン硬化触媒のＤＢＵを２重量部、シリコン系消泡剤を４重量部、微紛状シリカのアエロジル５０を１５．８重量部、アエロジル１３０を１．８重量部、硫酸バリウムＢ−３０を４４重量部、タルクのミクロエースＰ−３０を１１重量部、及び、マイカのＭＫ−１００を１１重量部、とを加えて攪拌し均一に混合させてポリイミドシロキサン溶液組成物（溶液粘度３６０ポイズ）を得た。
【００５９】
この溶液組成物は、約５℃で２週間放置しても、粘度変化は少なくスクリ−ン印刷可能であった。
この溶液組成物を用いて形成された硬化絶縁膜の電気絶縁性（体積抵抗）を測定したところ、５×１０^１３Ω・ｃｍであった。
この溶液組成物及び硬化絶縁膜についての評価結果を表２に示す。
また、この溶液組成物のフィラー成分を除いた樹脂成分からなる硬化絶縁膜の損失正接（ｔａｎδ）の温度変化を図１に示す。この組成からなる硬化絶縁膜のガラス転移温度は１１０℃であった。尚、図１の１１０℃のピークはエポキシ化合物成分に由来するガラス転移温度である。
【００６０】
実施例２
エポキシ樹脂として、エピコート１００７を５重量部とエピコート１００４を５重量部とを用いる以外は実施例１と同様にして、ポリイミドシロキサンの溶液組成物（３４０ポイズ）を得た。
この溶液組成物は、約５℃で２週間放置しても、粘度変化は少なくスクリ−ン印刷可能であった。
この溶液組成物及び硬化絶縁膜についての評価結果を表２に示す。
また、この溶液組成物のフィラー成分を除いた樹脂成分からなる硬化絶縁膜の損失正接（ｔａｎδ）の温度変化を図２に示す。この組成からなる硬化絶縁膜のガラス転移温度は１０９℃であった。尚、図２の１０９℃のピークはエポキシ化合物成分に由来するガラス転移温度である。
【００６１】
実施例３
エポキシ樹脂として、エピコート１００４を１０重量部用いる以外は実施例１と同様にして、ポリイミドシロキサンの溶液組成物（３００ポイズ）を得た。
この溶液組成物は、約５℃で２週間放置しても、粘度変化は少なくスクリ−ン印刷可能であった。
この溶液組成物を用いて形成された硬化絶縁膜の電気絶縁性（体積抵抗）を測定したところ、４×１０^１４Ω・ｃｍであった。
この溶液組成物及び硬化絶縁膜についての評価結果を表２に示す。
また、この溶液組成物のフィラー成分を除いた樹脂成分からなる硬化絶縁膜の損失正接（ｔａｎδ）の温度変化を図３に示す。この組成からなる硬化絶縁膜のガラス転移温度は１０５℃であった。尚、図３の１０５℃のピークはエポキシ化合物成分に由来するガラス転移温度である。
【００６２】
実施例４
エポキシ樹脂としてエピコート１００４を１０重量部用い、硬化触媒としてキュアゾール２Ｅ４ＭＺを０．３重量部用いる以外は実施例１と同様にして、ポリイミドシロキサンの溶液組成物（４８０ポイズ）を得た。
この溶液組成物は、約５℃で２週間放置しても、粘度変化は少なくスクリ−ン印刷可能であった。
この溶液組成物を用いて形成された硬化絶縁膜の電気絶縁性（体積抵抗）を測定したところ、１×１０^１４Ω・ｃｍであった。
この溶液組成物及び硬化絶縁膜についての評価結果を表２に示す。
また、この溶液組成物のフィラー成分を除いた樹脂成分からなる硬化絶縁膜の損失正接（ｔａｎδ）の温度変化を図４に示す。この組成からなる硬化絶縁膜のガラス転移温度は１１６℃であった。尚、図４の１１６℃のピークはエポキシ化合物成分に由来するガラス転移温度である。
【００６３】
実施例５
エポキシ樹脂としてハイカーＥＴＢＮ１３００×４０を１３．８重量部用いる以外は実施例１と同様にして、ポリイミドシロキサンの溶液組成物（３００ポイズ）を得た。
この溶液組成物は、約５℃で２週間放置しても、粘度変化は少なくスクリ−ン印刷可能であった。
この溶液組成物を用いて形成された硬化絶縁膜の電気絶縁性（体積抵抗）を測定したところ、２×１０^１３Ω・ｃｍであった。
この溶液組成物及び硬化絶縁膜についての評価結果を表２に示す。
また、この溶液組成物のフィラー成分を除いた樹脂成分からなる硬化絶縁膜の損失正接（ｔａｎδ）の温度変化を図５に示す。この組成からなる硬化絶縁膜のガラス転移温度は１２１℃であった。尚、図５の１２１℃のピークはエポキシ化合物成分に由来するガラス転移温度である。
【００６４】
実施例６
参考例２で得たポリイミドシロキサン溶液にＴＧを添加してポリイミドシロキサン濃度を３７％に調整した溶液を用いて、ポリイミドシロキサン１００重量部に対して表１に示す種類と量を配合し、ポリイミドシロキサンの溶液組成物（４３０ポイズ）を得た。
この溶液組成物は、約５℃で２週間放置しても、粘度変化は少なくスクリ−ン印刷可能であった。
この溶液組成物を用いて形成された硬化絶縁膜の電気絶縁性（体積抵抗）を測定したところ、１×１０^１３Ω・ｃｍであった。
この溶液組成物及び硬化絶縁膜についての評価結果を表２に示す。
また、この溶液組成物のフィラー成分を除いた樹脂成分からなる硬化絶縁膜の損失正接（ｔａｎδ）の温度変化を図６に示す。この組成からなる硬化絶縁膜のガラス転移温度は９５℃であった。尚、図６の９５℃のピークはエポキシ化合物成分に由来するガラス転移温度とポリイミドシロキサンのシロキサン骨格以外の芳香族鎖に由来するガラス転移温度とが重なったものである。
【００６５】
比較例１
エポキシ樹脂としてエピコート１５７Ｓ７０を１０重量部用いる以外は実施例１と同様にして、ポリイミドシロキサンの溶液組成物（３８０ポイズ）を得た。
この溶液組成物及び硬化絶縁膜についての評価結果を表２に示す。
また、この溶液組成物のフィラー成分を除いた樹脂成分からなる硬化絶縁膜の損失正接（ｔａｎδ）の温度変化を図７に示す。この組成からなる硬化絶縁膜のガラス転移温度は１４０℃付近から１８０℃付近までの幅広いピークを示した。また、１８０℃以上の温度になっても損失正接（ｔａｎδ）にブレ（測定値のバラツキ）は見られず硬化絶縁膜としてリジッドな状態が保持されている。尚、図７の１４０℃から１８０℃までの幅広いピークはエポキシ化合物成分に起因したものである。
【００６６】
【表１】

【００６７】
【表２】

【００６８】
【発明の効果】
本発明は、以上説明したような構成を有しているため、次のような効果を奏する。
すなわち、本発明は、基材に塗布後１２０℃程度以下の低温で加熱処理することによって硬化絶縁膜（保護膜）を得ることが可能であり、その硬化絶縁膜は基材や封止材料との密着性が良好であり、スズ潜りが３５μｍ以下の改良された耐スズメッキ性を有し、更に、ソリが発生し難く、耐熱性、耐ハンダフラックス性、耐溶剤性、耐薬品性、耐屈曲性、及び電気特性が優れ、フレキシブル配線基板などの基材上にスクリーン印刷などの方法で良好に塗布が可能であり、電気電子部品などの絶縁膜を形成するための印刷インキ又は塗布用ワニスとして好適な絶縁膜用組成物を提供することができる。
【図面の簡単な説明】
【図１】実施例１の絶縁膜用組成物のフィラー成分を除いた樹脂成分を用いて形成された硬化絶縁膜の損失正接（ｔａｎδ）の温度分布曲線
【図２】実施例２の絶縁膜用組成物のフィラー成分を除いた樹脂成分を用いて形成された硬化絶縁膜の損失正接（ｔａｎδ）の温度分布曲線
【図３】実施例３の絶縁膜用組成物のフィラー成分を除いた樹脂成分を用いて形成された硬化絶縁膜の損失正接（ｔａｎδ）の温度分布曲線
【図４】実施例４の絶縁膜用組成物のフィラー成分を除いた樹脂成分を用いて形成された硬化絶縁膜の損失正接（ｔａｎδ）の温度分布曲線
【図５】実施例５の絶縁膜用組成物のフィラー成分を除いた樹脂成分を用いて形成された硬化絶縁膜の損失正接（ｔａｎδ）の温度分布曲線
【図６】実施例６の絶縁膜用組成物のフィラー成分を除いた樹脂成分を用いて形成された硬化絶縁膜の損失正接（ｔａｎδ）の温度分布曲線
【図７】比較例１の絶縁膜用組成物のフィラー成分を除いた樹脂成分を用いて形成された硬化絶縁膜の損失正接（ｔａｎδ）の温度分布曲線
【図８】絶縁膜フィルム基材にＩＣなどのチップ部品などを実装した部品であって、配線パターン表面を先にスズメッキし次いでこの発明のポリイミドシロキサン絶縁膜用組成物からなる硬化絶縁膜（保護膜）を形成する手順で、絶縁フィルム基材にチップ部品を実装したときの一例の概略の断面図である。
【符号の説明】
１：ポリイミドフィルム
２：銅箔からなる配線パターン
３：メッキされたスズ層
４：絶縁用組成物からなる硬化絶縁膜（保護膜）
５：金バンプ５を用いた接合部位
６：ＩＣチップ
７：封止材料[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention is a solution composition comprising an organic solvent-soluble resin having a group having reactivity with an epoxy group and containing a polysiloxane skeleton and an epoxy compound, which is obtained by heat treatment. The cured insulating film obtained has a group having a reactivity with the epoxy group and has a glass transition temperature derived from an organic solvent-soluble resin component containing a polysiloxane skeleton and a glass transition temperature derived from the epoxy compound component. The present invention relates to a composition for an insulating film configured to be 160 ° C. or lower. The solution composition of the present invention can obtain a cured insulating film by applying heat treatment at a low temperature of about 120 ° C. or less after application to a substrate, and the cured insulating film adheres to the substrate or the sealing material. And has improved tin plating resistance with a tin dive of 35 μm or less. Furthermore, it is hardly warped, has excellent heat resistance, solvent resistance, chemical resistance, bending resistance, and electrical properties, and can be well applied to substrates such as flexible wiring boards by screen printing. Yes, it is used as a composition for an insulating film suitable as a printing ink or a coating varnish for forming an insulating film (a protective film, a solder resist, an interlayer insulating layer, etc.) of an electronic component or the like.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, the use of an epoxy resin, an aromatic polyimide resin, or the like as an insulating film (protective film) for an electric / electronic component is known in applications such as a solid-state element, a semiconductor integrated circuit, and a flexible wiring board. Epoxy resin has plating resistance and good adhesion to the base material, but on the other hand, it needs to be used in combination with a curing agent, etc. In addition, there are various problems such as flexibility, and the insulating film formed by thermosetting is rigid, has low flexibility, and is inferior in flexibility.
[0003]
In addition, since an aromatic polyimide resin is generally difficult to dissolve in an organic solvent, a coating film is formed using a solution of a precursor of an aromatic polyimide (aromatic polyamic acid), and then dried and heated at a high temperature for a long time. It is necessary to imidize by heat treatment to form an aromatic polyimide insulating film, and there is a problem that the electric or electronic member to be protected itself is thermally deteriorated.
[0004]
As a method for solving such a problem, for example, a composition for an insulating film containing a resin having a polysiloxane skeleton having high flexibility and high solubility in an organic solvent such as polyimidesiloxane and an epoxy resin ( For example, Patent Documents 1 and 2) are known. However, such a composition has a problem that, with an increase in the amount of the polysiloxane component, the adhesion to a certain sealing material is not sufficient, and further, the cured insulating film has tin plating resistance. Since the tin dive was about 100 μm, there was room for improvement.
[0005]
When forming an insulating film such as an electric / electronic component, an insulating tape base material having a wiring pattern formed of a copper foil such as a TAB tape protects a circuit except for a connection portion such as an inner lead or a solder ball terminal. The composition for an insulating film is applied on the substrate and heat-treated to form an insulating film (protective film). Next, the copper foil surface of the connection portion is plated with tin, and thereafter, electronic components such as ICs are connected.
When the tin plating is performed, tin enters into the gap between the insulating film and the copper foil from the end of the insulating film, and tin dive occurs. Further, the copper foil is cut off at this portion to form a hole. Such tin dipping and the hole contact with the copper foil may cause breakage due to stress concentration when the copper foil is bent.
As the size of electrical and electronic components has been reduced, the thickness of copper foil used for electrical and electronic components has been reduced, and for example, when a thin copper foil having a thickness of about 12 μm has been used, the above-described tin submersion and a hole in which the copper foil has been excavated. The occurrence is a major obstacle in securing the reliability of the electric / electronic circuit.
[0006]
For this reason, a method has been proposed in which an insulating tape base material on which a wiring pattern is formed of copper foil is first tin-plated, and then a composition for an insulating film is applied to portions other than the connection portion and heat-treated to form an insulating film. ing. (For example, see Patent Document 3)
Tin plating is usually about 0.5 μm thick and is used to form a eutectic with a gold bump to form a connection. This tin plating layer is unstable, and whiskers grow rapidly at room temperature. This may cause a short circuit. For this reason, annealing treatment is performed at a temperature of about 120 ° C. within several hours after tin plating, the lower layer of the tin plating layer is stabilized as an alloy of tin and copper, and the surface layer of the tin plating layer is eutectic with the gold bump. Hold as pure tin to form connections.
In this method, the above-mentioned problem of tin dipping and hole contact of the copper foil does not occur. However, when heat treatment is performed at a temperature of about 160 ° C. to harden the composition for the insulating film after tin plating, all tin diffuses into copper and is alloyed with the gold bump to form a eutectic to form a connection portion. The problem arises that a pure tin layer cannot be retained for the purpose.
In order to solve the above-mentioned problems, a hardened insulating film is formed by a heat treatment at about 120 ° C. or lower, which is an annealing temperature of a tin plating layer, so that the function as an insulating film (protective film) can be exhibited. There has been a demand for a composition for an insulating film.
[0007]
[Patent Document 1]
JP-A-4-36321
[Patent Document 2]
JP-A-7-304950
[Patent Document 3]
JP-A-6-342969
[0008]
[Problems to be solved by the invention]
An object of the present invention is to obtain a cured insulating film (protective film) by applying a heat treatment at a low temperature of about 120 ° C. or less after application to a base material, and the cured insulating film is formed of a base material and a sealing material. Good tin adhesion, improved tin plating resistance with tin dive of 35 μm or less, less warpage, heat resistance, solder flux resistance, solvent resistance, chemical resistance, bending resistance Excellent in properties and electrical properties, can be applied well by a method such as screen printing on a substrate such as a flexible wiring board, and as a printing ink or a coating varnish for forming an insulating film such as an electric / electronic part. An object of the present invention is to provide a suitable composition for an insulating film.
[0009]
[Means for Solving the Problems]
That is, the present invention provides (a) 100 parts by weight of an organic solvent-soluble resin having a group having reactivity with an epoxy group and containing a polysiloxane skeleton, (b) 1 to 50 parts by weight of an epoxy compound, and And (C) a composition for an insulating film containing an organic solvent, wherein the cured insulating film has a group having reactivity with the epoxy group when heat-treated to form a cured insulating film; A composition for an insulating film, wherein a glass transition temperature derived from an organic solvent-soluble resin component containing a polysiloxane skeleton and a glass transition temperature derived from the epoxy compound component are 160 ° C. or less. About things.
Further, the present invention provides an organic solvent-soluble resin having a group reactive with an epoxy group and containing a polysiloxane skeleton, comprising a tetracarboxylic acid component and a diaminopolysiloxane represented by the general formula (1). A diamine component comprising 45 to 95 mol%, 0.5 to 40 mol% of an aromatic diamine having a polar group, and 0 to 54.5 mol% of a diamine other than the diaminopolysiloxane and the aromatic diamine having a polar group. Being an organic solvent-soluble polyimide siloxane obtained from
Embedded image

(Where R ₁ Represents a divalent hydrocarbon group or an aromatic group; ₂ Independently represents a monovalent hydrocarbon group or an aromatic group, and n1 represents an integer of 3 to 50. )
It also relates to the epoxy equivalent of the epoxy compound exceeding 800 and less than 4000.
The present invention also relates to the composition for an insulating film, which further contains (d) a curing accelerator, and that the curing accelerator is a tertiary amine.
Further, in the present invention, the composition for an insulating film preferably further contains (e) 20 to 150 parts by weight of a fine filler, and the fine filler contains at least finely divided silica, talc, mica, or sulfuric acid. Containing any one of barium.
Further, the present invention provides a cured insulating film obtained by heat-treating any one of the above-mentioned insulating film compositions, and a method of applying the above-mentioned one of the above-mentioned insulating film compositions to a substrate, and then heating the composition to 50 ° C to 210 ° C. The present invention relates to a method of forming a cured insulating film by performing heat treatment at a temperature of ℃.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
In the present invention, the glass transition temperature was measured by a solid dynamic viscoelasticity measuring device. In a solid dynamic viscoelasticity measuring device, sinusoidal deformation of a constant frequency is applied to a sample at each temperature, and a force generated in the sample is detected to obtain an elastic modulus. The glass transition is the temperature at which the micro-Brownian motion of a specific segment in a resin freezes or opens, and the inflection point in the storage elastic modulus and loss elastic modulus temperature dispersion curves obtained by a solid dynamic viscoelasticity measurement device, respectively. And yield peaks. Further, the glass transition temperature appears as a peak in a loss tangent temperature dispersion curve which is a ratio of a loss elastic modulus to a storage elastic modulus. In the present invention, the glass transition temperature was determined as a temperature showing a peak in a temperature dispersion curve of the loss tangent described above.
[0011]
A composition in which a resin having reactivity with an epoxy group and containing a polysiloxane skeleton as a main component and an epoxy compound added thereto can form a cured insulating film by a crosslinking reaction by heat treatment. However, this cured insulating film has poor adhesion to certain sealing materials because the polysiloxane skeleton contained in the resin constituting the main component has low adhesion to organic materials such as epoxy resin. It is considered that the epoxy compound is a small component and has a crosslinked structure when the cured insulating film is formed by heat treatment, so that the epoxy compound has an effective effect for improving the adhesion to the sealing material. It was thought that it could not be demonstrated.
[0012]
The composition for an insulating film of the present invention is characterized in that when a cured insulating film is formed by heat treatment, the cured insulating film has a reactivity with an epoxy group and a resin component (segment) containing a polysiloxane skeleton. One feature is that the adhesiveness with the sealing material can be improved by configuring the glass transition temperature derived from the epoxy compound component (segment) to be 160 ° C. or less. It is.
[0013]
The adhesion between the cured insulating film and the sealing material will be specifically described. Usually, after the cured insulating film is formed, a liquid sealing material is disposed in contact with the cured insulating film by coating or the like, and the sealing material is cured by heat treatment. The heat treatment temperature for curing the sealing material is usually about 160 ° C. Since the resin component contained in the cured insulating film has a glass transition temperature of 160 ° C. or less, the resin component having a glass transition temperature of 160 ° C. or less contained in the cured insulating film in a heat treatment step of curing the sealing material ( The segments) have increased mobility, allowing for closer chemical or physical interaction with the sealing material (higher mobility since it has not fully cured) at the interface with the sealing material. In the present invention, the resin component (segment) in the cured insulating film having a glass transition temperature of 160 ° C. or less needs to be capable of potentially having a close chemical or physical interaction with the sealing material. Preferred are a resin component (segment) and an epoxy compound component (segment) having a group having reactivity with an epoxy group and containing a polysiloxane skeleton.
[0014]
In the present invention, the glass transition temperature of a resin component (segment) having reactivity with an epoxy group and containing a polysiloxane skeleton changes depending on the content of the polysiloxane skeleton. When the content of the polysiloxane skeleton is small, for example, in the case of polyimide siloxane, the proportion of an aromatic chain component such as an aromatic tetracarboxylic acid component or an aromatic diamine component having an imide ring is relatively increased. The transition temperature may exceed 160 ° C. The organic solvent-soluble resin having a group having reactivity with an epoxy group and containing a polysiloxane skeleton has a polysiloxane skeleton of 30% by weight or more, preferably 40% by weight or more, more preferably 50% by weight or more. It is preferred to contain.
[0015]
By increasing the content of the polysiloxane skeleton, the glass transition temperature of the resin component (segment) having reactivity with the epoxy group and containing the polysiloxane skeleton can be reduced to 160 ° C. or less, further 50 ° C. or less, particularly room temperature or less. Become. It is particularly preferable that the glass transition temperature be equal to or lower than room temperature, since the obtained cured insulating film has flexibility at room temperature.
As described above, when the glass transition temperature of a resin component (segment) having reactivity with an epoxy group and containing a polysiloxane skeleton is lowered, the resin component has reactivity with an epoxy group and a polysiloxane skeleton. The resin component (segment) showing the highest glass transition temperature among the glass transition temperatures derived from the resin component containing and the epoxy compound component is the epoxy compound component (segment).
[0016]
In the present invention, in order to adjust the cured insulating film to have a glass transition temperature derived from the epoxy compound component (segment) of 160 ° C. or less, the crosslinked structure of the epoxy compound of the cured insulating film becomes too fine. It is particularly important that the epoxy compound has a relatively large epoxy equivalent, that is, an epoxy compound having an epoxy equivalent of more than 800. When the crosslinked structure formed by the epoxy compound of the insulating cured film becomes fine, the glass transition temperature derived from the epoxy compound component exceeds 160 ° C.
[0017]
In the present invention, a glass transition temperature derived from a resin component having a group having a reactivity with an epoxy group of the cured insulating film and containing a polysiloxane skeleton and a glass transition temperature derived from an epoxy compound component, The temperature is preferably 160 ° C or lower, preferably 140 ° C or lower, more preferably 130 ° C or lower. It is particularly preferable that the glass transition of these components (segments) is completed at 160 ° C. or lower. That the glass transition is completed at 160 ° C. or lower means that the entire peak in the temperature variance curve of the loss tangent is within a range of 160 ° C. or lower.
[0018]
The resin component or epoxy compound component having a group having reactivity with an epoxy group and containing a polysiloxane skeleton has one or more glass transition temperatures derived therefrom. Having a plurality of glass transition temperatures means that a resin component and an epoxy compound component having a group having reactivity with an epoxy group and containing a polysiloxane skeleton are each composed of a plurality of components (segments). At this time, in the present invention, it is preferable that the plurality of glass transition temperatures are all 160 ° C. or less.
In the present invention, the lower limit of the glass transition temperature derived from the resin component and the epoxy compound component having a group having a reactivity with an epoxy group and containing a polysiloxane skeleton is not particularly limited. Usually, it has the lowest glass transition temperature of about -150 ° C or higher, especially about -100 ° C, which is derived from the polysiloxane skeleton.
[0019]
In the present invention, an organic solvent-soluble resin having a group having reactivity with an epoxy group and containing a polysiloxane skeleton is an aromatic dicarboxylic anhydride group or an aromatic dicarboxylic acid half ester in a molecule. A group, a carboxylic acid group, a hydroxyl group, an amide group, and the like, having a group in which a substantial curing reaction does not occur at room temperature with an epoxy group, for example, a curing reaction can occur at a relatively high temperature of 80 ° C. or higher, and A resin containing a polysiloxane skeleton in the main chain. Preferably, in order to improve heat resistance and the like, the main chain includes a flexible polysiloxane skeleton and rigid segments such as a benzene ring and an imide ring.
In the present invention, an organic solvent-soluble resin having a group having reactivity with an epoxy group and containing a polysiloxane skeleton is not limited, but polyimide siloxane as shown below is particularly suitable. . Hereinafter, the present invention will be described using polyimide siloxane as an example.
[0020]
In the present invention, polyimide siloxane suitable as an organic solvent-soluble resin having a group having reactivity with an epoxy group and containing a polysiloxane skeleton is preferably a tetracarboxylic acid component, a diaminopolysiloxane 45 to 95%. And a diamine component comprising 0.5 to 40 mol% of an aromatic diamine having a polar group, and 0 to 54.5 mol% of a diamine other than the diaminopolysiloxane and the aromatic diamine having a polar group. It can be obtained by a reaction in an organic solvent using a tetracarboxylic acid component in a ratio of about 1.0 to 1.2 mol with respect to about 1 mol of the diamine component, preferably about 1 mol. If the content of the tetracarboxylic acid component is too large, the printing characteristics of the obtained composition for a polyimidesiloxane insulating film are undesirably deteriorated.
[0021]
Specific examples of the tetracarboxylic acid component of the polyimidesiloxane include 2,3,3 ′, 4′-biphenyltetracarboxylic acid, 3,3 ′, 4,4′-biphenyltetracarboxylic acid, 3,3 ′, 4,4′-diphenylethertetracarboxylic acid, 3,3 ′, 4,4′-diphenylsulfonetetracarboxylic acid, 3,3 ′, 4,4′-benzophenonetetracarboxylic acid, 2,2-bis ( 3,4-benzenedicarboxylic acid) hexafluoropropane, pyromellitic acid, 1,4-bis (3,4-benzenedicarboxylic acid) benzene, 2,2-bis [4- (3,4-phenoxydicarboxylic acid) phenyl ] Propane, 2,3,6,7-naphthalenetetracarboxylic acid, 1,2,5,6-naphthalenetetracarboxylic acid, 1,2,4,5-naphthalenetetracarboxylic acid, 1,4,5,8 -Aromatic tetracarboxylic acids such as naphthalenetetracarboxylic acid and 1,1-bis (2,3-dicarboxyphenyl) ethane, or esterified products of dianhydrides and lower alcohols thereof, and cyclopentane Alicyclic tetracarboxylic acids such as tetracarboxylic acid, 1,2,4,5-cyclohexanetetracarboxylic acid, and 3-methyl-4-cyclohexene-1,2,4,5-tetracarboxylic acid, or the like. Preference is given to acid dianhydrides and esterified products of lower alcohols. Among these, 2,3,3 ′, 4′-biphenyltetracarboxylic acid and 3,3 ′, 4,4′-diphenylethertetracarboxylic acid, or their acid dianhydrides, Esterified products of lower alcohols are preferred because they have excellent solubility in organic solvents when used as polyimide siloxane.
Further, in the present invention, it is preferable that the aromatic tetracarboxylic acid component as exemplified above is contained in the tetracarboxylic acid component of the polyimidesiloxane in an amount of 80 mol% or more, particularly 85% to 100%.
[0022]
As the tetracarboxylic acid component of the polyimidesiloxane in the present invention, it is preferable to use a tetracarboxylic dianhydride that can be easily reacted with a diamine.
In the case where the amount of the tetracarboxylic dianhydride used is 1.05 times or more mol of the diamine and an unreacted anhydride ring remains, it may be left as it is, but is subjected to ring-opening half esterification with an esterifying agent. You may. The amount of the alcohol used as the esterifying agent is preferably 1.1 to 20 times equivalent, particularly preferably 1.5 to 5 times equivalent of the excess tetracarboxylic dianhydride. When the proportion of alcohols is small, unreacted anhydrous rings remain, and the storage stability of the composition becomes poor, and excess alcohols become poor solvents to precipitate insolubles or lower the solid content concentration. This makes it difficult to form a coating film by printing, which is not preferable.
When an esterifying agent is used, the reaction solution may be used as it is, but it is also possible to use excess alcohol by heating or distilling off under reduced pressure.
[0023]
In the present invention, the diamine component of the polyimidesiloxane is 45 to 95 mol% of a diaminopolysiloxane represented by the following general formula (1), 0.5 to 40 mol% of an aromatic diamine having a polar group, and the diaminopolysiloxane It is particularly preferable that the diamine other than the aromatic diamine having a polar group is used at a ratio of 0 to 54.5 mol% (usually 0 to 30 mol%). If any one of the components is too large or too small and deviates from these ranges, the solubility of the obtained polyimide siloxane in the organic solvent is reduced, the compatibility with other organic compounds is deteriorated, or the wiring board is It is not preferable because the radius of curvature of the insulating film formed thereon becomes small and the bending resistance decreases, and the adhesion to the base material and the heat resistance decrease.
[0024]
The diaminopolysiloxane represented by the following general formula (1) constituting the diamine component of the polyimidesiloxane in the present invention is preferably a compound represented by the formula: ₁ Is a divalent hydrocarbon group having 1 to 6 carbon atoms or a phenylene group, particularly a propylene group, wherein R2 is independently an alkyl group having 1 to 5 carbon atoms or a phenyl group, and n1 is 3 -50, especially 3-20. If n1 is less than 3, the bending resistance of the obtained insulating film is deteriorated, which is not preferable. On the other hand, if n1 exceeds 50, the reactivity with the tetracarboxylic acid component is lowered, and the molecular weight of the obtained polyimide siloxane becomes low. Since the solubility of the polyimide siloxane in the organic solvent is low, the compatibility with other organic components in the composition is poor, or the solvent resistance of the obtained insulating film is low, the above-described degree is preferable. It is. When the diaminopolysiloxane comprises a mixture of two or more, n1 is calculated from the amino equivalent.
Embedded image

(Where R ₁ Represents a divalent hydrocarbon group or an aromatic group; ₂ Independently represents a monovalent hydrocarbon group or an aromatic group, and n1 represents an integer of 3 to 50. )
[0025]
Examples of specific compounds of the diaminopolysiloxane include α, ω-bis (2-aminoethyl) polydimethylsiloxane, α, ω-bis (3-aminopropyl) polydimethylsiloxane, and α, ω-bis (4 -Aminophenyl) polydimethylsiloxane, α, ω-bis (4-amino-3-methylphenyl) polydimethylsiloxane, α, ω-bis (3-aminopropyl) polydiphenylsiloxane, α, ω-bis (4- Aminobutyl) polydimethylsiloxane and the like.
[0026]
The aromatic diamine having a polar group constituting the diamine component of the polyimidesiloxane in the present invention is an aromatic diamine having a polar group having a reactivity with an epoxy group in a molecule, and is preferably represented by the following general formula (2): Is a diamine represented by
Embedded image

(Wherein X and Y are each independently a direct bond, CH ₂ , C (CH ₃ ) ₂ , C (CF ₃ ) ₂ , O, benzene ring, SO ₂ And r1 represents COOH or OH, n2 is 1 or 2, n3 and n4 are each independently 0, 1 or 2, preferably 0 or 1, and at least one of n3 and n4 is 1 or 2 It is. )
[0027]
Examples of the diamine compound represented by the general formula (2) include diaminophenol compounds such as 2,4-diaminophenol, 3,3′-diamino-4,4′-dihydroxybiphenyl, and 4,4. '-Diamino-3,3'-dihydroxybiphenyl, 4,4'-diamino-2,2'-dihydroxybiphenyl, 4,4'-diamino-2,2', 5,5'-tetrahydroxybiphenyl and the like Hydroxybiphenyl compounds, 3,3'-diamino-4,4'-dihydroxydiphenylmethane, 4,4'-diamino-3,3'-dihydroxydiphenylmethane, 4,4'-diamino-2,2'- Dihydroxydiphenylmethane, 2,2-bis [3-amino-4-hydroxyphenyl] propane, 2,2-bis [4-amino-3-hydroxyphenyl] pro Hydroxydiphenylalkane compounds such as 2,2-bis [3-amino-4-hydroxyphenyl] hexafluoropropane and 4,4′-diamino-2,2 ′, 5,5′-tetrahydroxydiphenylmethane; , 3'-Diamino-4,4'-dihydroxydiphenyl ether, 4,4'-diamino-3,3'-dihydroxydiphenyl ether, 4,4'-diamino-2,2'-di Hydroxydiphenyl ether compounds such as hydroxydiphenyl ether and 4,4'-diamino-2,2 ', 5,5'-tetrahydroxydiphenyl ether; 3,3'-diamino-4,4' -Dihydroxydiphenylsulfone, 4,4'-diamino-3,3'-dihydroxydiphenylsulfone, 4,4'-diamino-2,2'-dihydroxydife Hydroxysulfone compounds such as sulfone, 4,4'-diamino-2,2 ', 5,5'-tetrahydroxydiphenylsulfone, 2,2-bis [4- (4-amino-3-hydroxyphenoxy) phenyl Bis (hydroxyphenoxyphenyl) alkane compounds such as propane, bis (hydroxyphenoxy) biphenyl compounds such as 4,4'-bis (4-amino-3-hydroxyphenoxy) biphenyl, and 2,2-bis [4 Examples thereof include diamine compounds having an OH group such as bis (hydroxyphenoxyphenyl) sulfone compounds such as-(4-amino-3-hydroxyphenoxy) phenyl] sulfone.
[0028]
Further, examples of the diamine compound represented by the general formula (2) include benzenecarboxylic acids such as 3,5-diaminobenzoic acid and 2,4-diaminobenzoic acid, and 3,3′-diamino-4,4′-. Dicarboxybiphenyl, 4,4'-diamino-3,3'-dicarboxybiphenyl, 4,4'-diamino-2,2'-dicarboxybiphenyl, 4,4'-diamino-2,2 ', 5 Carboxybiphenyl compounds such as 5'-tetracarboxybiphenyl, 3,3'-diamino-4,4'-dicarboxydiphenylmethane, 4,4'-diamino-3,3'-dicarboxydiphenylmethane, 4,4'- Diamino-2,2'-dicarboxydiphenylmethane, 2,2-bis [3-amino-4-carboxyphenyl] propane, 2,2-bis [4-amino-3-carboxyphenyl Carboxydiphenylalkane compounds such as propane, 2,2-bis [3-amino-4-carboxyphenyl] hexafluoropropane, and 4,4′-diamino-2,2 ′, 5,5′-tetracarboxybiphenyl; 3,3'-diamino-4,4'-dicarboxydiphenyl ether, 4,4'-diamino-3,3'-dicarboxydiphenyl ether, 4,4'-diamino-2,2'- Carboxydiphenyl ether compounds such as dicarboxydiphenyl ether and 4,4'-diamino-2,2 ', 5,5'-tetracarboxydiphenyl ether; 3,3'-diamino-4,4 '-Dicarboxydiphenylsulfone, 4,4'-diamino-3,3'-dicarboxydiphenylsulfone, 4,4'-diamino-2,2', 5,5'-tetracarboxydiphenyl Carboxydiphenyl sulfone compounds such as sulfone, bis (carboxyphenoxyphenyl) alkane compounds such as 2,2-bis [4- (4-amino-3-carboxyphenoxy) phenyl] propane, and 4,4′-bis (4 Bis (carboxyphenoxy) biphenyl compounds such as -amino-3-carboxyphenoxy) biphenyl and bis (carboxyphenoxyphenyl) sulfone such as 2,2-bis [4- (4-amino-3-carboxyphenoxy) phenyl] sulfone Diamine compounds having a COOH group such as compounds can be given.
[0029]
The diamine other than the diaminopolysiloxane and the polar group-containing aromatic diamine constituting the diamine component of the polyimidesiloxane in the present invention is not particularly limited, but is an aromatic diamine represented by the following general formula (3). Is preferred.
Embedded image

(Wherein X and Y are each independently a direct bond, CH ₂ , C (CH ₃ ) ₂ , C (CF ₃ ) ₂ , O, benzene ring, SO ₂ And n5 is 1 or 2. )
[0030]
The aromatic diamine represented by the general formula (3) is specifically, 1,4-diaminobenzene, 1,3-diaminobenzene, 2,4-diaminotoluene, 1,4-diamino-2,5- Diamines containing one benzene such as dihalogenobenzene, bis (4-aminophenyl) ether, bis (3-aminophenyl) ether, bis (4-aminophenyl) sulfone, bis (3-aminophenyl) ) Sulfone, bis (4-aminophenyl) methane, bis (3-aminophenyl) methane, bis (4-aminophenyl) sulfide, bis (3-aminophenyl) sulfide, 2,2-bis (4-aminophenyl) Propane, 2,2-bis (3-aminophenyl) propane, 2,2-bis (4-aminophenyl) hexafluoropropane, o-dianisidine, Diamines containing two benzenes such as tolidine and tolidinesulfonic acid, 1,4-bis (4-aminophenoxy) benzene, 1,4-bis (3-aminophenoxy) benzene, 1,4-bis (4- Aminophenyl) benzene, 1,4-bis (3-aminophenyl) benzene, α, α′-bis (4-aminophenyl) -1,4-diisopropylbenzene, α, α′-bis (4-aminophenyl) Diamines containing three benzenes such as -1,3-diisopropylbenzene, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (4-aminophenoxy) phenyl Hexafluoropropane, 2,2-bis [4- (4-aminophenoxy) phenyl] sulfone, 4,4 ′-(4-aminophenoxy) biphenyl, 9, Diamine compounds such as diamines containing 4 or more benzenes, such as 9-bis (4-aminophenyl) fluorene and 5,10-bis (4-aminophenyl) anthracene.
In addition, an aliphatic diamine compound such as hexamethylene diamine and diaminododecane can be used together with the diamine.
[0031]
The polyimidesiloxane in the present invention is not particularly limited, but can be obtained, for example, by the following method.
(1) A method of using substantially equimolar amounts of a tetracarboxylic acid component and a diamine component and continuously polymerizing and imidizing at 15 to 250 ° C. in an organic polar solvent to obtain a polyimide siloxane.
(2) Separate the tetracarboxylic acid component and the diamine component from each other, and polymerize and imidize an excess amount of the tetracarboxylic acid component and the amine component (for example, diaminopolysiloxane) in an organic polar solvent at 15 to 250 ° C. An imide siloxane oligomer having an acid anhydride group (or an acid or an ester thereof) at an end having an average degree of polymerization of about 1 to 10 is prepared, and a tetracarboxylic acid component and an excess amount of a diamine component are separately added to an organic polar solvent for 15 minutes. Polymerization and imidization at ~ 250 ° C to prepare an imide oligomer having an amino group at the terminal having an average degree of polymerization of about 1 to 10, and then mixing both such that the acid component and the diamine component are substantially equimolar. And reacting at 15 to 60 ° C., and further raising the temperature to 130 to 250 ° C. to obtain a block type polyimide siloxane.
(3) A tetracarboxylic acid component and a diamine component are used in substantially equimolar amounts, and are first polymerized at 20 to 80 ° C. in an organic polar solvent to obtain a polyamic acid, and then the polyamic acid is imidized to obtain a polyimide siloxane. Method.
[0032]
Examples of the organic polar solvent used for obtaining the polyimidesiloxane by the above method include a nitrogen-containing solvent such as N, N-dimethylacetamide, N, N-diethylacetamide, N, N-dimethylformamide, N, N-solvent. Solvents containing a sulfur atom, such as diethylformamide, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, N-methylcaprolactam, for example, dimethylsulfoxide, diethylsulfoxide, dimethylsulfone, diethylsulfone, hexa Phenol solvents such as methylsulfformamide, such as cresol, phenol, xylenol, etc., diglyme solvents such as diethylene glycol dimethyl ether (diglyme), triethylene glycol dimethyl ether (triglyme), tetraglyme, etc. , The solvent having an oxygen atom in the molecule, such as acetone, methanol, ethanol, ethylene glycol, dioxane, tetrahydrofuran, and other pyridine, and the like tetramethylurea. If necessary, an aromatic hydrocarbon-based solvent such as benzene, toluene, or xylene, or another organic solvent such as solvent naphtha or benzonitrile may be used in combination.
[0033]
In the present invention, as the polyimide siloxane, those obtained by any of the above methods (1) to (3) may be used, but at least 3% by weight or more, preferably 5 to 60% by weight in the organic solvent, Particularly, it can be dissolved at a high concentration of about 5 to 50%, and the solution viscosity at 25C (E-type rotational viscometer) is preferably 1 to 10,000 poise, particularly preferably 1 to 100 poise.
In the present invention, the polyimidesiloxane preferably has a higher molecular weight, and more preferably has a higher imidization ratio. The logarithmic viscosity (measurement concentration: 0.5 g / 100 ml, solvent: N-methyl-2-pyrrolidone, measurement temperature: 30 ° C.) as a measure of molecular weight is 0.15 or more, especially 0.16 to 2 It is preferable from the viewpoint of mechanical properties such as strength and elongation of the cured film. Further, the imidization ratio determined from the infrared absorption spectrum is preferably 90% or more, particularly preferably 95% or more, and more preferably substantially 100%.
[0034]
The epoxy compound constituting the composition for a polyimidesiloxane insulating film of the present invention is a compound having a plurality of epoxy groups, and has an epoxy equivalent of more than 800, especially 850 or more and less than 4000, particularly 3000 or less, and And a liquid or solid epoxy resin is preferable. When the epoxy equivalent of the epoxy compound is 800 or less, it is not easy to reduce the glass transition temperature of the cured insulating film to 160 ° C. or less, resulting in poor adhesion to the sealing material. When the epoxy equivalent of the epoxy compound is 4000 or more, the glass transition temperature when the cured insulating film is formed can be 160 ° C. or less, but the obtained insulating film composition is easily increased in viscosity and easy to handle. Not.
Specifically, for example, Epicoat 1055, Epicoat 1004, Epicoat 1004AF, Epicoat 1007, Epicoat 1009, Epicoat 1010, EPICLON4050, EPICLON7050, AM-040-P, HM091 manufactured by Dainippon Ink and Chemicals, Inc. , HM-101, etc., bisphenol A epoxy resin such as Epicoat 4004P, Epicoat 4007P, Epicoat 4110 manufactured by Japan Epoxy Resin Co., Ltd., Hiker ETBN1300 × 40 manufactured by Ube Industries, Ltd., and Nagase Chemtech Preferable examples include Denarex R-45EPT manufactured by Co., Ltd.
[0035]
In the present invention, the amount of the epoxy compound used is 1 to 50 parts by weight, preferably 2 to 30 parts by weight, based on 100 parts by weight of the polyimide siloxane. If the amount is too large, gelation is likely to occur or the adhesion will be reduced. If the amount is too small, the heat resistance and chemical resistance of the cured insulation after heat treatment will deteriorate, so the above range is preferred.
[0036]
In the present invention, it is preferable to add a curing accelerator that promotes a curing reaction of the epoxy compound such as hydrazine, imidazole, and tertiary amine together with the epoxy compound.
In particular, when a tertiary amine is added as a curing accelerator, the composition for an insulating film can easily obtain a cured insulating film (protective film) by heat treatment at a low temperature of about 120 ° C. or less after application to a substrate. It is very suitable because it can be performed. As the tertiary amines that can be suitably used in the present invention, specifically, 1,8-diazabicyclo [5.4.0] -7-undecene, N, N-dimethylbenzylamine, N, N, N ', N'-tetramethylhexanediamine, triethylenediamine, 2-dimethylaminomethylphenol, 2,4,6-tris (dimethylaminomethyl) phenol, dimorpholinodiethylether, 1,4-dimethylpiperazine, cyclohexyldimethylamine And the like.
The curing accelerator such as a tertiary amine is used in an amount of 0.5 to 20 parts by weight, preferably 1 to 10 parts by weight, based on 100 parts by weight of the polyimide siloxane. If the amount is more than 20 parts by weight, the solvent resistance and the electrical properties deteriorate, and if the amount is too small, it takes a long time to cure at low temperature, so the above range is preferable.
[0037]
As the organic solvent constituting the composition for a polyimidesiloxane insulating film of the present invention, the organic solvent used for the reaction for preparing the polyimidesiloxane can be used as it is, but preferably, a nitrogen-containing solvent, for example, N, N-dimethylacetamide, N, N-diethylacetamide, N, N-dimethylformamide, N, N-diethylformamide, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, N- Oxygen-containing solvents such as methylcaprolactam and other sulfur-containing atomic solvents such as dimethylsulfoxide, diethylsulfoxide, dimethylsulfone, diethylsulfone, and hexamethylsulfonamide; phenol-based solvents such as cresol, phenol and xylenol Diglyme solvents such as diethylene glycol Ethyleneglycol dimethyl - ether (diglyme), triethylene glycol - ethyleneglycol dimethyl - ether (triglyme), and tetraglyme, acetone, acetophenone, propiophenone, ethylene glycol, dioxane, tetrahydrofuran and the like. In particular, N-methyl-2-pyrrolidone, N, N-dimethylsulfoxide, N, N-dimethylformamide, N, N-diethylformamide, N, N-dimethylacetamide, N, N-diethylacetamide, γ-butyrolactone, tri Ethylene glycol dimethyl ether, diethylene glycol dimethyl ether and the like can be preferably used.
[0038]
Further, the composition for an insulating film of the present invention preferably contains a fine filler. The fine inorganic filler may have any form, but preferably has an average particle diameter of 0.001 to 15 μm, particularly preferably 0.005 to 10 μm. It is not preferable to use a material out of this range, since cracks are generated when the obtained coating film is bent or the bent portion is whitened. Preferable examples of the fine filler include fine inorganic fillers such as fine powder silica, talc, mica, and barium sulfate, and fine organic fillers such as crosslinked NBR fine particles.
[0039]
The amount of the fine inorganic filler used is preferably 20 to 150 parts by weight in total with respect to 100 parts by weight of an organic solvent-soluble resin having a group reactive with an epoxy group and containing a polysiloxane skeleton, preferably Is from 40 to 125 parts by weight. If the amount used is too large or too small, cracks will occur due to bending of the coating film, and printability, solder heat resistance, and copper foil discoloration will be affected, so the above range is preferable. Further, a fine inorganic filler, in particular, a combination of fine powder silica and at least one of talc, mica and barium sulfate is used, and the fine silica powder has a group having a reactivity with an epoxy group and has a polysiloxane skeleton. 1 to 50 parts by weight, especially 5 to 40 parts by weight, at least one of talc, mica or barium sulfate is used in an amount of 20 to 130 parts by weight based on 100 parts by weight of the organic solvent-soluble resin to be contained, and the printability is It is particularly preferable in consideration of the performance of the obtained cured insulating film.
[0040]
Further, in the composition for an insulating film of the present invention, a predetermined amount of an organic coloring pigment and an inorganic coloring pigment, for example, an organic solvent-soluble resin having a group having reactivity with an epoxy group and containing a polysiloxane skeleton. About 0 to 100 parts by weight can be used for 100 parts by weight.
Further, in the insulating film composition of the present invention, a predetermined amount of an antifoaming agent, for example, 100 parts by weight of an organic solvent-soluble resin having a group having a reactivity with an epoxy group and containing a polysiloxane skeleton. On the other hand, about 0.1 to 10 parts by weight can be used.
[0041]
The composition for an insulating film of the present invention includes a resin having a group having reactivity with an epoxy group and containing a polysiloxane skeleton, such as a polyimidesiloxane, an epoxy compound, a fine filler, and an organic solvent. Can be easily obtained by mixing a predetermined amount and uniformly stirring and mixing. When mixed, they can be mixed in an organic solvent to form a solution composition. When mixed with an organic solvent to form a solution composition, a polymerization solution of a resin having a group reactive with an epoxy group and containing a polysiloxane skeleton, for example, a polyimidesiloxane, may be used as it is, or the polymerization solution may be used. May be diluted with an appropriate organic solvent. Examples of the organic solvent include organic polar solvents that can be used when obtaining the resin, for example, polyimide siloxane. However, it is preferable to use one having a boiling point of 140 ° C. or higher and 210 ° C. or lower. In particular, when an organic solvent having a boiling point of 180 ° C. or more, particularly 200 ° C. or more (for example, methyltriglyme) is used, the dissipation by evaporation of the solvent is extremely reduced. It is optimal because it can be performed favorably without any trouble. The organic solvent is used in an amount of about 60 to 200 parts by weight with respect to 100 parts by weight of a resin having a group having reactivity with an epoxy group and containing a polysiloxane skeleton, for example, polyimidesiloxane.
[0042]
The composition for an insulating film of the present invention preferably has a solution viscosity of 100 to 600 poise at room temperature (25 ° C.) from the viewpoint of workability, physical properties of the solution, and properties of the protective film.
[0043]
The composition for an insulating film of the present invention can be used for forming an insulating film (protective film) of an electric / electronic component on which a chip component such as an IC chip is mounted.
For example, after printing on a pattern surface of an insulating film having a wiring pattern formed of a conductive metal foil by screen printing or the like so that the thickness of the dry film becomes about 3 to 60 μm, the applied film is applied to the surface. Heating and drying at a temperature of about 100 ° C. for about 5 to 60 minutes, then about 100 to 210 ° C., preferably 120 to 200 ° C. for 5 to 120 minutes, preferably about 10 to 60 minutes; Preferably, the elastic modulus is 0.1 to 20 kgf / mm ² It is preferable to form an insulating film.
[0044]
Furthermore, the composition for an insulating film of the present invention is cured by a heat treatment at a low temperature of about 50 to 130 ° C., particularly about 60 to 120 ° C., so that the insulating film having the above-mentioned good performance can be easily formed. Can be.
For this reason, the insulating film composition of the present invention can form a cured insulating film by a heat treatment at a relatively high temperature of about 160 ° C. or more in the mounting step, or 130 ° C. or less, preferably 120 ° C. The cured insulating film can be formed by a heat treatment at a relatively low temperature of the order of or less. After the cured insulating film is formed by a relatively low-temperature heat treatment of 130 ° C. or less, preferably about 120 ° C. or less, a relatively high-temperature heat treatment of about 160 ° C. or more may be further performed. .
[0045]
In other words, when mounting a chip component such as an IC chip on an insulating film substrate, for example, the insulating film composition of the present invention is mounted by a procedure of forming an insulating film for protecting a wiring pattern and then tinning. Alternatively, it is also possible to mount the wiring pattern by first performing tin plating on the wiring pattern and then forming an insulating film for protecting the wiring pattern.
The procedure of tin plating first, for example, when mounting on an insulating film substrate, is as follows. That is, (1) the surface of the wiring pattern of the copper foil formed on the surface of the insulating film substrate is tin-plated. {Circle over (2)} The insulating film composition of the present invention is applied or printed on a predetermined portion of the surface of the insulating film substrate, and is heated and cured at a relatively low temperature of about 120 ° C. or less to form an insulating film (protective film). ) Is formed. (3) An electronic component such as an IC chip is mounted on an inner lead portion or the like of a wiring pattern on which an insulating film is not formed by using a gold bump or the like. At this time, heat treatment is performed for a short time but about 400 ° C. or more so that the connection portion forms a gold-tin eutectic. (4) Next, the IC chip and the like are protected by a sealing material or the like. At this time, heat treatment is performed at a temperature of about 160 ° C. to cure the sealing material and the like.
[0046]
FIG. 8 is a schematic cross-sectional view showing an example in which the insulating film composition of the present invention is used in the above-described tin plating procedure to form an insulating film of an electronic component.
In FIG. 8, a wiring pattern 2 is formed of, for example, 12 μm thick copper foil on a surface of, for example, a polyimide film 1 having a thickness of 25 μm, and the surface thereof is covered with a plated tin layer 3 having a thickness of, for example, 0.5 μm. . Further, the insulating film 4 made of the insulating composition of the present invention forms a protective film having a thickness of, for example, 10 μm on those surfaces except for the connection portion of the inner lead. An IC chip 6 is mounted on the connection portion using a gold bump 5 and protected by, for example, an epoxy resin-based sealing material 7.
[0047]
Further, the composition for an insulating film of the present invention has good adhesion to a conductive metal and various materials for insulation, and the cured product has suitable mechanical strength and electrical insulation performance. It can be suitably used not only as a protective film for electronic components but also as an interlayer insulating film. Furthermore, the composition for an insulating film of the present invention can be suitably used as a heat-resistant adhesive which can be pressed at a low temperature and is heat-resistant.
[0048]
【Example】
Hereinafter, the present invention will be described with reference to Examples and Comparative Examples. The present invention is not limited to the following embodiments.
[0049]
The measurement and evaluation in each example were performed by the following methods.
(Solution viscosity)
Using an E-type viscometer (manufactured by Tokyo Keiki Co., Ltd.), the viscosity was measured at a temperature of 25 ° C. and a rotation speed of 10 rpm.
(Evaluation of printability)
If the screen printing is possible, the formed film has no pinhole, and there is no outflow at the end of the film, ○ indicates that screen printing is not possible, or the film has pinholes, or the film has an edge. Is indicated by x when there is an outflow.
[0050]
(Evaluation of cured insulating film)
The evaluation of the cured insulating film was performed on the cured insulating film sample that was heat-treated as described below, depending on the evaluation items.
That is, the solvent resistance, the glass transition temperature, and the evaluation of the adhesion to the sealing material were evaluated by heating at about 120 ° C. or less when the composition for the insulating film was applied on the conductor wiring that had been subjected to tin plating in the mounting step. In consideration of hardening, the test was performed on a sample that had been heat-treated at 80 ° C. for 30 minutes and then at 120 ° C. for 1 hour. However, in the evaluation of the adhesion with the sealing material, since the sealing material was further dropped and applied to the sample surface and cured by heating at 160 ° C., the heat treatment was performed twice at 120 ° C. and 160 ° C. in total. It will be.
Other evaluations of the cured insulating film were performed at 80 ° C. for 30 minutes and then at 160 ° C. for 1 hour, taking into consideration that a heat treatment at about 160 ° C. is finally performed to cure the sealing material in the mounting process. This was performed on the heat-treated sample.
[0051]
Evaluation of solvent resistance:
After immersing 0.5 g of a sheet-like sample cured so as to have a thickness of about 75 μm in 100 ml of acetone (25 ° C.) for 30 minutes, the results are shown in terms of% by weight of acetone-soluble matter.
Glass-transition temperature:
The glass transition temperature of the resin component (segment) is basically not affected by the contained filler. Here, the glass transition temperature was measured for a sample prepared using a composition consisting only of a resin component containing no filler. This is because when a filler-containing sample is used, a peak indicating a glass transition temperature tends to be unclear in a chart showing a change in loss tangent (tan δ) with temperature. The measurement may be performed on a sample prepared using a composition containing a filler.
Specifically, a sample cured in a sheet shape having a thickness of 75 μm is cut out into a strip shape having a width of 5 mm and a length of 30 mm, and a solid viscoelastic analyzer RSAII manufactured by Rheometrics Scientific Inc. is used. Measurement was performed 30 seconds after the temperature reached each set temperature at a temperature step of 2 ° C. in a nitrogen stream at a frequency of 10 Hz, the temperature was raised to the next temperature, and the measurement was repeated to determine the temperature change of the loss tangent (tan δ).
Explaining in a specific example, for example, the temperature change of the loss tangent (tan δ) of the cured insulating film obtained from the composition of Example 1 described below is as shown in FIG. In this figure, the peaks at −100 ° C., 5 ° C., and 110 ° C. indicate the glass transition temperatures derived from the polysiloxane component of polyimidesiloxane, the aromatic chain component of polyimidesiloxane, and the epoxy compound component, respectively. Note that the variation in the measurement points observed at 130 ° C. or higher in FIG. 1 is due to the fact that each component exceeds the glass transition temperature and as a result, the cured insulating film becomes soft as a whole and the elastic modulus to be measured varies. The state in which such variation occurs is that substantially all the resin components (segments) of the cured insulating film have increased motility, and the interface between the cured insulating film and the sealing material is more tightly bound to the sealing material by chemical or physical interaction. It is considered that the action is enabled to enhance the adhesion. On the other hand, when no such variation is observed, it indicates that the cured insulating film is in a rigid state as a whole even when the temperature exceeds the glass transition temperature.
[0052]
Evaluation of adhesion to IC sealing material:
A composition for an insulating film is applied to a glossy surface of a 35 μm thick electrolytic copper foil to a thickness of 30 μm and cured, and an IC chip encapsulating material CEL-C-5020 (manufactured by Hitachi Chemical Co., Ltd.) having a thickness of about 1 mm is formed on the cured film. A sample was applied by dripping in a circle having a diameter of about 0.5 cm and cured at 160 ° C. to obtain a sample. The sample was bent by hand and the degree of peeling of the sealing resin was observed. The case where cohesive failure occurred in the cured insulating film is 、, the case where cohesive failure of the cured insulating film and peeling of the cured insulating film / sealing material interface coexist is Δ, and the case where the cured insulating film film / sealing material interface peels is ×. Indicated by.
[0053]
Measurement of electrical insulation (volume resistance):
Using this solution composition, a cured insulating film having a thickness of about 75 μm was formed, and the electrical insulation (volume resistance) of the film was measured according to JIS C-2103.
Measurement of tensile modulus:
A sheet sample cured to a thickness of about 75 μm was cut into a width of 1 cm and a length of 15 cm and used for the test. Measured according to ASTM D882.
[0054]
Tin dive measurement:
An electroless tin plating solution (LT-34, manufactured by Shipley Fur East Co., Ltd.) was obtained by applying a 30 μm thick composition for an insulating film on a glossy surface of a 35 μm thick electrolytic copper foil (manufactured by Mitsui Mining & Smelting Co., Ltd.). Then, tin plating was performed for 4 minutes at a temperature of 70 ° C., and the width (distance from the end) of a portion where tin infiltrated at the end of the insulating film and tin dipping occurred was measured.
[0055]
The epoxy resin, curing catalyst, and filler used in each of the following examples will be described. (Epoxy resin)
Epicoat 1007: manufactured by Japan Epoxy Resin, epoxy equivalent 2000
Epicoat 1004: manufactured by Japan Epoxy Resin, epoxy equivalent 900
Hiker ETBN1300 × 40: manufactured by Ube Industries, epoxy equivalent 2770, xylene 50% solution
Epicoat 157S70: manufactured by Japan Epoxy Resin, epoxy equivalent 210
(Curing catalyst)
DBU: Aldrich, 1,8-diazabicyclo [5.4.0] -7-undecene
Cureazole 2E4MZ: 2-ethyl-4-methylimidazole manufactured by Shikoku Chemicals
(Fine powder silica)
Aerosil 50: manufactured by Nippon Aerosil Co., Ltd., average particle size: 30 nm
Aerosil 130: manufactured by Nippon Aerosil Co., Ltd., average particle size: 16 nm
(Barium sulfate)
Barium sulfate B-30: manufactured by Sakai Chemical Industry Co., Ltd., average particle size 0.3 μm
(talc)
Microace P-3: manufactured by Nippon Talc, average particle size 1.8 μm
(Mica)
MK-100: manufactured by Corp Chemical, average particle size 2.6 μm
[0056]
Reference Example 1 (Production of polyimide siloxane)
In a glass flask having a capacity of 500 ml, 58,84 g (0.2 mol) of 2,3,3 ', 4'-biphenyltetracarboxylic dianhydride and triglyme as a solvent (hereinafter sometimes abbreviated as TG). 120 g was charged and heated and stirred at 180 ° C. under a nitrogen atmosphere. 154.7 g (0.17 mol) of α, ω-bis (3-aminopropyl) polydimethylsiloxane (amino equivalent 455) and 70 g of TG were added, and the mixture was heated and stirred at 180 ° C. for 60 minutes. Further, 8.59 g (0.03 mol) of 4,4′-diamino-3,3′-dicarboxyphenylmethane and 23.4 g of TG were added to the reaction solution, and the mixture was heated and stirred at 180 ° C. for 5 hours, and then filtered. Was. The obtained polyimide siloxane reaction solution was a solution having a polymer solid content concentration of 50% by weight and ηinh of 0.18. The imidation ratio was substantially 100%.
[0057]
Reference Example 2 (Production of polyimide siloxane)
A glass flask having a capacity of 500 ml was charged with 58.84 g (0.2 mol) of 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride and 170 g of TG, and heated and stirred at 180 ° C. under a nitrogen atmosphere. After cooling to around 100 ° C., 127.4 g (0.14 mol) of α, ω-bis (3-aminopropyl) polydimethylsiloxane (amino equivalent 455) and 50 g of TG were added, and the mixture was heated and stirred at 180 ° C. for 60 minutes. After cooling to around room temperature, 13.52 g (0.03 mol) of 2,2-bis [4- (4-aminophenoxy) phenyl] propane and 4.56 g (3.55 g of 3,5-diaminobenzoic acid) were added to the reaction solution. 0.03 mol) and 79 g of TG, and the mixture was heated and stirred at 180 ° C. for 5 hours, and then filtered. The obtained polyimide siloxane reaction solution was a solution having a polymer solid content concentration of 40% by weight and η inh of 0.20. The imidation ratio was substantially 100%.
[0058]
Example 1
In a glass container, the polyimide siloxane solution obtained in Reference Example 1, 10 parts by weight of an epoxy resin epicoat 1007 per 100 parts by weight of polyimide siloxane, 2 parts by weight of DBU of a tertiary amine curing catalyst, and silicone-based defoaming 4 parts by weight of the agent, 15.8 parts by weight of Aerosil 50 of finely divided silica, 1.8 parts by weight of Aerosil 130, 44 parts by weight of barium sulfate B-30, and 11 parts by weight of Microace P-30 of talc , And 11 parts by weight of mica MK-100 were added, and the mixture was stirred and uniformly mixed to obtain a polyimidesiloxane solution composition (solution viscosity: 360 poise).
[0059]
This solution composition showed little change in viscosity and was capable of screen printing even when left at about 5 ° C. for 2 weeks.
When the electrical insulation (volume resistance) of the cured insulating film formed using this solution composition was measured, it was 5 × 10 ^Thirteen Ω · cm.
Table 2 shows the evaluation results of the solution composition and the cured insulating film.
FIG. 1 shows the temperature change of the loss tangent (tan δ) of the cured insulating film made of the resin component excluding the filler component of this solution composition. The glass transition temperature of the cured insulating film having this composition was 110 ° C. The peak at 110 ° C. in FIG. 1 is the glass transition temperature derived from the epoxy compound component.
[0060]
Example 2
A polyimidesiloxane solution composition (340 poise) was obtained in the same manner as in Example 1 except that 5 parts by weight of Epicoat 1007 and 5 parts by weight of Epicoat 1004 were used as the epoxy resin.
This solution composition showed little change in viscosity and was capable of screen printing even when left at about 5 ° C. for 2 weeks.
Table 2 shows the evaluation results of the solution composition and the cured insulating film.
FIG. 2 shows the temperature change of the loss tangent (tan δ) of the cured insulating film composed of the resin component excluding the filler component of this solution composition. The glass transition temperature of the cured insulating film having this composition was 109 ° C. The peak at 109 ° C. in FIG. 2 is the glass transition temperature derived from the epoxy compound component.
[0061]
Example 3
A polyimidesiloxane solution composition (300 poise) was obtained in the same manner as in Example 1 except that 10 parts by weight of Epicoat 1004 was used as the epoxy resin.
This solution composition showed little change in viscosity and was capable of screen printing even when left at about 5 ° C. for 2 weeks.
When the electrical insulation (volume resistance) of the cured insulating film formed using this solution composition was measured, it was 4 × 10 ¹⁴ Ω · cm.
Table 2 shows the evaluation results of the solution composition and the cured insulating film.
FIG. 3 shows the temperature change of the loss tangent (tan δ) of the cured insulating film composed of the resin component excluding the filler component of this solution composition. The glass transition temperature of the cured insulating film having this composition was 105 ° C. The peak at 105 ° C. in FIG. 3 is the glass transition temperature derived from the epoxy compound component.
[0062]
Example 4
A polyimidesiloxane solution composition (480 poise) was obtained in the same manner as in Example 1 except that 10 parts by weight of Epicoat 1004 was used as an epoxy resin and 0.3 parts by weight of Curezol 2E4MZ was used as a curing catalyst.
This solution composition showed little change in viscosity and was capable of screen printing even when left at about 5 ° C. for 2 weeks.
When the electrical insulation (volume resistance) of the cured insulating film formed using this solution composition was measured, it was 1 × 10 ¹⁴ Ω · cm.
Table 2 shows the evaluation results of the solution composition and the cured insulating film.
FIG. 4 shows the temperature change of the loss tangent (tan δ) of the cured insulating film composed of the resin component excluding the filler component of this solution composition. The glass transition temperature of the cured insulating film having this composition was 116 ° C. The peak at 116 ° C. in FIG. 4 is the glass transition temperature derived from the epoxy compound component.
[0063]
Example 5
A polyimidesiloxane solution composition (300 poise) was obtained in the same manner as in Example 1 except that 13.8 parts by weight of Hiker ETBN1300 × 40 was used as the epoxy resin.
This solution composition showed little change in viscosity and was capable of screen printing even when left at about 5 ° C. for 2 weeks.
When the electrical insulation (volume resistance) of the cured insulating film formed using this solution composition was measured, it was 2 × 10 ^Thirteen Ω · cm.
Table 2 shows the evaluation results of the solution composition and the cured insulating film.
FIG. 5 shows the temperature change of the loss tangent (tan δ) of the cured insulating film composed of the resin component excluding the filler component of this solution composition. The glass transition temperature of the cured insulating film having this composition was 121 ° C. The peak at 121 ° C. in FIG. 5 is the glass transition temperature derived from the epoxy compound component.
[0064]
Example 6
Using the solution obtained by adding TG to the polyimide siloxane solution obtained in Reference Example 2 to adjust the concentration of the polyimide siloxane to 37%, blending the types and amounts shown in Table 1 with respect to 100 parts by weight of the polyimide siloxane. Was obtained (430 poise).
This solution composition showed little change in viscosity and was capable of screen printing even when left at about 5 ° C. for 2 weeks.
When the electrical insulation (volume resistance) of the cured insulating film formed using this solution composition was measured, it was 1 × 10 ^Thirteen Ω · cm.
Table 2 shows the evaluation results of the solution composition and the cured insulating film.
FIG. 6 shows the temperature change of the loss tangent (tan δ) of the cured insulating film made of the resin component excluding the filler component of this solution composition. The glass transition temperature of the cured insulating film having this composition was 95 ° C. Note that the peak at 95 ° C. in FIG. 6 is obtained by overlapping the glass transition temperature derived from the epoxy compound component with the glass transition temperature derived from an aromatic chain other than the siloxane skeleton of the polyimidesiloxane.
[0065]
Comparative Example 1
A polyimidesiloxane solution composition (380 poise) was obtained in the same manner as in Example 1 except that 10 parts by weight of Epicoat 157S70 was used as the epoxy resin.
Table 2 shows the evaluation results of the solution composition and the cured insulating film.
FIG. 7 shows the temperature change of the loss tangent (tan δ) of the cured insulating film composed of the resin component excluding the filler component of this solution composition. The glass transition temperature of the cured insulating film having this composition showed a broad peak from about 140 ° C. to about 180 ° C. Even at a temperature of 180 ° C. or more, the loss tangent (tan δ) shows no fluctuation (variation in measured values), and the rigid state is maintained as the cured insulating film. The broad peak from 140 ° C. to 180 ° C. in FIG. 7 is due to the epoxy compound component.
[0066]
[Table 1]

[0067]
[Table 2]

[0068]
【The invention's effect】
Since the present invention has the configuration as described above, it has the following effects.
That is, according to the present invention, a cured insulating film (protective film) can be obtained by performing a heat treatment at a low temperature of about 120 ° C. or less after application to a base material. Has good tin adhesion and improved tin plating resistance with a tin dive of 35 μm or less, hardly generates warp, heat resistance, solder flux resistance, solvent resistance, chemical resistance, bending resistance Excellent in properties and electrical properties, can be applied well by a method such as screen printing on a substrate such as a flexible wiring board, and as a printing ink or a coating varnish for forming an insulating film such as an electric / electronic part. A suitable composition for an insulating film can be provided.
[Brief description of the drawings]
FIG. 1 is a temperature distribution curve of a loss tangent (tan δ) of a cured insulating film formed using a resin component excluding a filler component of the insulating film composition of Example 1.
FIG. 2 is a temperature distribution curve of loss tangent (tan δ) of a cured insulating film formed by using a resin component excluding a filler component of the insulating film composition of Example 2.
FIG. 3 is a temperature distribution curve of a loss tangent (tan δ) of a cured insulating film formed using a resin component excluding a filler component of the insulating film composition of Example 3.
FIG. 4 is a temperature distribution curve of loss tangent (tan δ) of a cured insulating film formed using a resin component excluding a filler component of the insulating film composition of Example 4.
FIG. 5 is a temperature distribution curve of a loss tangent (tan δ) of a cured insulating film formed using a resin component excluding a filler component of the insulating film composition of Example 5.
FIG. 6 is a temperature distribution curve of a loss tangent (tan δ) of a cured insulating film formed using a resin component excluding a filler component of the insulating film composition of Example 6.
FIG. 7 is a temperature distribution curve of loss tangent (tan δ) of a cured insulating film formed by using a resin component excluding a filler component of the insulating film composition of Comparative Example 1.
FIG. 8 shows a component in which a chip component such as an IC is mounted on an insulating film base material, wherein the surface of a wiring pattern is first plated with tin, and then a cured insulating film (protection) comprising the polyimidesiloxane insulating film composition of the present invention is formed. FIG. 3 is a schematic cross-sectional view of an example when a chip component is mounted on an insulating film substrate in a procedure for forming a film.
[Explanation of symbols]
1: Polyimide film
2: Wiring pattern made of copper foil
3: Plated tin layer
4: Cured insulating film (protective film) made of insulating composition
5: bonding part using gold bump 5
6: IC chip
7: Sealing material

Claims (9)

(A) 100 parts by weight of an organic solvent-soluble resin having a group having reactivity with an epoxy group and containing a polysiloxane skeleton, (b) 1 to 50 parts by weight of an epoxy compound, and (C) an organic solvent A composition for an insulating film comprising, when heat-treated to form a cured insulating film, the cured insulating film has a group having reactivity with the epoxy group and contains a polysiloxane skeleton. A composition for an insulating film, wherein a glass transition temperature derived from an organic solvent-soluble resin component and a glass transition temperature derived from the epoxy compound component are 160 ° C. or lower. An organic solvent-soluble resin having a group having reactivity with an epoxy group and containing a polysiloxane skeleton comprises a tetracarboxylic acid component, 45 to 95 mol% of a diaminopolysiloxane represented by the general formula (1), Organic solvent obtained from 0.5 to 40 mol% of an aromatic diamine having a polar group and 0 to 54.5 mol% of a diamine other than the diaminopolysiloxane and the aromatic diamine having a polar group The composition for an insulating film according to claim 1, wherein the composition is a soluble polyimide siloxane.

(In the formula, R ₁ represents a divalent hydrocarbon group or an aromatic group, R ₂ independently represents a monovalent hydrocarbon group or an aromatic group, and n1 represents an integer of 3 to 50.) 3. The composition for an insulating film according to claim 1, wherein the epoxy equivalent of the epoxy compound is more than 800 and less than 4000. The composition for an insulating film according to any one of claims 1 to 3, further comprising (d) a curing accelerator. The composition for an insulating film according to any one of claims 1 to 4, wherein the curing accelerator is a tertiary amine. The composition for an insulating film according to any one of claims 1 to 5, further comprising (e) 20 to 150 parts by weight of a fine filler. The composition for an insulating film according to any one of claims 1 to 6, wherein the fine filler contains at least one of finely divided silica, talc, mica, and barium sulfate. A cured insulating film obtained by heat-treating the composition for an insulating film according to claim 1. A method for forming a cured insulating film by applying the composition for an insulating film according to any one of claims 1 to 7 to a substrate and then performing a heat treatment at 50 ° C to 210 ° C.

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