JP3971498B2 - Laminated body - Google Patents

Description

（式中、Ｒ₁ 〜Ｒ₈ は同一でも異なっていてもよい水素、ハロゲン、アルキル基又はアルコシキ基を表わす）
また、このポリアミック酸層を２層以上の異なる構造からなるポリアミック酸層としてもよく、さらに接着性の向上などを目的としてカップリング剤や酸化防止剤などを添加することもできる。
【００１３】
次に、本発明の積層体に用いられる感光性樹脂は、必須の構成成分として下記の成分を含有する酸現像型感光性樹脂である。
（１）アミン当量が１００〜１０，０００のアミン含有酸溶解性樹脂
（２）１分子中に２以上のエチレン性不飽和結合を有する単量体
（３）光重合開始剤
【００１４】
ここでいうアミン含有酸溶解性樹脂とは、その構造中にアミンを含有する樹脂であり、その重量平均分子量が好ましくは１００〜１，０００，０００、より好ましくは１，０００〜５００，０００のものである。また、含有されるアミンとしては、１級、２級又は３級のいずれのアミンでも差し支えない。また、アミン含有酸溶解性樹脂中のアミン１モル当たりの分子量で定義されるアミン当量は、１００〜１０，０００、好ましくは２００〜２，０００である。アミン当量が１００より小さいと、感光性樹脂の酸による現像速度が大きくなりすぎ、その制御が困難である上に、現像工程での感光性樹脂の膨潤という問題が起こりやすくなる。また、アミン当量が１０，０００より大きいと、酸による現像を行うのが困難となる。
【００１５】
本発明の積層体に用いられる好ましいアミン含有酸溶解性樹脂は、下記一般式（１）で表わされる樹脂である。
【化５】

（式中、ｍ及びｎはそれぞれの構成成分のモル比率を表わし、ｍ＋ｎ＝１００、ｍ＝１〜９９である。Ｒ₁ は任意の２価の有機残基であり、Ｒ₂ 及びＲ₃ は水素又は任意の１価の有機残基を表わし、Ｒ₄ 〜Ｒ₆ は同一でも異なっていてもよい水素、ハロゲン又は１価の有機残基を表わし、Ｒ₇ 〜Ｒ₁₀は同一でも異なっていてもよい水素、ハロゲン又はアミンを含有しない１価の有機残基を表わす）
【００１６】
そして、より好ましいアミン含有酸溶解性樹脂は、下記一般式（２）で表わされる樹脂である。
【化６】

（式中、ｍ及びｎはそれぞれの構成成分のモル比率を表わし、ｍ＋ｎ＝１００、ｍ＝１〜９９である。Ｒ₁ 及びＲ₂ は水素又はメチル基を表わし、Ｒ₃ は任意の２価の有機残基を表わし、Ｒ₄ 及びＲ₅ は水素又はアルキル基を表わし、Ｒ₆ はアミンを含有しない任意の１価の有機残基を表わす）
【００１７】
このようなアミン含有酸溶解性樹脂は、アミン含有構成単位とアミン非含有構成単位とからなる共重合樹脂である。アミン含有構成単位を構成する単量体としては、例えば２−（ジメチルアミノ）エチルメタクリレート、２−（ジエチルアミノ）エチルメタクリレート、２−（ジメチルアミノ）エチルアクリレート、２−（ジエチルアミノ）エチルアクリレート等のアミノ基含有メタクリレート（アクリレート）類から選ばれた単量体の１種又は２種以上が挙げられる。また、アミン非含有構成単位を構成する単量体としては、例えばメチルメタクリレート、エチルメタクリレート、ブチルメタクリレート、イソブチルメタクリレート、ラウリルメタクリレート、メチルアクリレート、エチルアクリレート、ｎ−デシルメタクリレート、２−エチルヘキシルメタクリレート、イソデシルメタクリレート等のメタクリレート（アクリレート）類や、ヒドロキシエチルメタクリレート、ヒドロキシプロピルメタクリレート、ヒドロキシエチルアクリレート、ヒドロキシプロピルアクリレート等のヒドロキシアルキルメタクリレート（アクリレート）類の他に、アクリロニトリル、スチレン、ヒドロキシスチレン、酢酸ビニルなどから選ばれた単量体の１種又は２種以上が挙げられる。
【００１８】
また、感光性樹脂中の第２の必須成分は、１分子中に２以上のエチレン性不飽和結合を有する単量体である。ここでいう単量体としては、任意の置換基又は隣接基を有するエチレン性不飽和結合を１分子中に２以上有する化合物である。このような単量体としては、例えば多官能アクリレート、多官能メタクリレート、多官能アリル化合物、多官能ビニルエーテルなどが挙げられ、反応速度の観点から好ましくは多官能アクリレート又は多官能メタクリレートである。なお、ここでいう多官能とは官能基数が２以上であることを意味する。
【００１９】
多官能アクリレートを具体的に例示すると、トリエチレングリコールジアクリレート、ポリエチレングリコールジアクリレート、ネオペンチルグリコールジアクリレート、ヘキサンジオールジアクリレート、ジメチロール−トリシクロデカンジアクリレート、ジメチロール−プロパントリアクリレート、ペンタエリスリトールヘキサアクリレート、ジペンタエリスリトールヘキサアクリレートや２官能以上のエポキシ化合物のアクリル酸との反応物などが挙げられる。また、多官能メタクリレートとしては、エチレングリコールジメタクリレート、ジエチレングリコールジメタクリレート、ブタンジオールジメタクリレート、ヘキサンジオールジメタクリレート、トリメチロールプロパントリメタクリレート、トリエチレングリコールジメタクリレート、ネオペンチルグリコールジメタクリレートや２官能以上のエポキシ化合物とメタアクリル酸との反応物などが挙げられる。このような１分子中に２以上のエチレン性不飽和結合を有する単量体を用いることで、光照射により光重合開始剤より発生したラジカルや酸等の活性種により、エチレン性不飽和結合が反応し、それによって感光性樹脂が酸に対し不溶化する。
【００２０】
さらに、感光性樹脂中の第３の必須成分は、光重合開始剤である。本発明に用いられる光重合開始剤は、ラジカル発生型と酸発生型があり、合わせて用いられる１分子中に２以上のエチレン性不飽和結合を有する単量体の種類によって選択することができる。そして、１分子中に２以上のエチレン性不飽和結合を有する単量体としてアクリレート又はメタクリレートを用いる場合には、ラジカル発生型の光重合開始剤を選択するのがよい。
【００２１】
光重合開始剤を具体的に例示すると、アセトフェノン、２，２−ジエトキシアセトフェノン、ｐ−ジメチルアセトフェノン、ｐ−ジメチルアミノプロピオフェノン、ジクロロアセトフェノン、トリクロロアセトフェノン、ｐ−ｔｅｒｔ−ブチルアセトフェノン等のアセトフェノン類、ベンゾフェノン、２−クロロベンゾフェノン、ｐ，ｐ’−ビスジメチルアミノベンゾフェノン等のベンゾフェノン類、ベンジル、ベンゾイン、ベンゾインメチルエーテル、ベンゾインイソプロピルエーテル、ベンゾインイソブチルエーテル等のベンゾインエーテル類、ベンジルジメチルケタール、チオキサントン、２−クロロチオキサントン、２，４−ジエチルチオキサントン、２−メチルチオキサントン、２−イソプロピルチオキサントン等のイオウ化合物、２−エチルアントラキノン、オクタメチルアントラキノン、１，２−ベンズアントラキノン、２，３−ジフェニルアントラキノン等のアントラキノン類、ベンゾイルパーオキサイド、クメンパーオキシド等の有機過酸化物、２−メルカプトベンゾイミダゾール、２−メルカプトベンゾオキサゾール、２−メルカプトベンゾチアゾール等のチオール化合物、アゾビスイソブチルニトリルなどが挙げられる。
【００２２】
これらの光重合開始剤は、単独で用いてもよいし、２種以上を併用してもよい。また、それ自体では光重合開始剤として作用しないが、上記の化合物と組み合わせて用いることにより、光重合開始剤の能力を増大させ得るような化合物を添加することもできる。そのような化合物としては、例えばベンゾフェノンと組み合わせて使用すると効果のあるトリエタノールアミン等の第３級アミンなどを挙げることができる。
【００２３】
また、本発明に用いられる感光性樹脂の成分としては、上記必須成分以外に、流動性、タック性、発色性、保存安定性などの調節を目的として、フィラー、発色剤、紫外線吸収剤、重合禁止剤、顔料、染料などを添加してもよい。
【００２４】
本発明の積層体の製造は、特に限定されるものでなく任意の方法が採用できるが、以下の方法が簡便であり、生産性の観点からも好ましい。まず、金属箔上にポリアミック酸溶液を塗布した後、乾燥してポリアミック酸層を形成する。その際、乾燥温度はイミド化反応等の副反応を防止するために、２００℃以下であることが好ましい。次いで、ポリアミック酸層の上に上記感光性樹脂溶液を塗布し、乾燥して感光性樹脂層を形成する。その際の乾燥温度は、感光性樹脂の熱的な架橋反応等を防止するために、２００℃以下であることが好ましい。
【００２５】
本発明の積層体は、異物混入や機械的なダメージを防止するために感光性樹脂表面にさらに保護層を形成したり、保護用のフィルムを貼り付けることも可能であり、また好ましい。
【００２６】
本発明の積層体を用いて、以下の工程により金属箔上でポリイミドのパターニングを行うことができる。
（１）フォトマスクを通して感光性樹脂の必要な部分に可視光又は紫外線を照射する工程
（２）感光性樹脂の現像工程
（３）ポリアミック酸のエッチング工程
（４）感光性樹脂の剥離工程
（５）ポリアミック酸のイミド化工程
【００２７】
このような工程により高精度にパターニングされたポリイミド層を形成することができる。さらに、本発明の積層体を特開平８−４５，２１３号公報などに開示されたような配線付サスペンションに適用する場合には、上記工程の後にスパッタリングやめっきなどによりポリイミド上に導体形成することで可能となる。
【００２８】
本発明の積層体を用いることで、耐熱性や信頼性に優れた高精度なポリイミドのパターニングを金属箔上で行うことが可能であり、種々の用途への応用が可能である。特に、ＨＤＤサスペンションに適用した場合、耐熱性や信頼性に加え、低アウトガス性などにも優れており、極めて好適である。
【００２９】
【実施例】
以下、実施例に基づいて本発明を具体的に説明する。なお、実施例における線膨張係数及びアミン当量の測定は次のとおりである。
（１）膨張係数の測定には、サーモメカニカルアナライザー（セイコー電子株式会社製、ＴＭＡ−１００）を用い、２５０℃まで昇温しさらにその温度で２０分保持した後、１０℃／分の速度で冷却して２４０℃から１００℃までの平均線膨張率を求めた。
（２）アミン含有酸溶解性樹脂のアミン当量の測定については、まずアミン含有酸溶解性樹脂溶液をアミン含有酸溶解性樹脂量が１ｇになるように量りとり、エチルセルソルブと水の重量比で１：１の混合溶液中に溶解して、１００ｍｌになるように正確に希釈した。次にその樹脂溶液２５ｍｌを自動滴定装置（平沼産業株式会社製、ＣＯＭＴＩＴＥ−５００）を用いて、０．０２モル／ｌの乳酸水溶液で滴定し、ｐＨが７となった時点を終点として、それまでに要した乳酸水溶液量Ｖｍｌから次式を用いて算出した。
アミン当量（ｇ／モル）＝1(g)×25(ml)/100(ml)/0.02(モル/l)/1000/ Ｖ(ml)
（３）加工精度については、直径が１０μｍ刻みで異なる円形のパターンを有するフォトマスクを用い、良好な形状を有するポリイミドの最小穴直径を目視により判断した。また、別の方法として、幅１００μｍのラインと幅１００μｍのギャップが交互にパターン化されたフォトマスクを用いて加工し、そのポリイミド層断面を観察してエッチファクターを算出して求めた。エッチファクター（ｆ）は下記の算出式を用いた。
ｆ＝２ｄ／（ｔ₁ −ｔ₂ ）
（式中、ｔ₁ はポリイミドパターン断面の台形の下底の長さ、ｔ₂ は断面の台形の上底の長さ、及びｄはポリイミド層の厚さを表す）
【００３０】
また、実施例等に用いられる略号は以下のとおりである。
ＭＭＡ ：メチルメタクリレート
ＨＯＭＡ ：２−ヒドロキシエチルメタクリレート
ＤＭＭＡ ：２−（ジメチルアミノ）エチルメタクリレート
ＭＤＥＧＭＡ：メトキシジエチレングリコールメタクリレート
ＡＩＢＮ ：アゾビスイソブチロニトリル
ＥＧＭＥ ：エチレングリコールモノエチルエーテル
ＤＰＨＡ ：ジペンタエリスリトールヘキサアクリレート
ＰＴＡ ：ペンタエリスリトールテトラアクリレート
ＴＭＰＴＡ ：トリメチロールプロパントリアクリレート
ＴＸ ：２，４−ジエチルチオキサントン
ＡＭ ：ｐ−ジメチルアミノ安息香酸イソアミルエステル
ＤＭＰＥ ：２，２−ジメトキシ−１，２−ジフェニルエタン−１−オン
ＭＡＢＡ ：４，４’−ジアミノ−２’−メトキシベンズアニリド
ＤＡＰＥ ：４，４’−ジアミノジフェニルエーテル
ＰＤＡ ：ｐ−フェニレンジアミン
ＰＭＤＡ ：ピロメリット酸二無水物
ＢＴＤＡ ：３，４，３’，４’−ベンゾフェノンテトラカルボン酸二無水物
ＤＭＡｃ ：Ｎ，Ｎ−ジメチルアセトアミド
【００３１】
合成例１
ＭＭＡ４００重量部、ＨＯＭＡ１００重量部、ＤＭＭＡ５００重量部、ＡＩＢＮ１５重量部、ＥＧＭＥ１０００重量部を冷却器、温度計、攪拌装置を取り付けた３リットルセパラブルフラスコに入れ、攪拌しながらマントルヒーターを用いて内温を７０℃まで上昇させた。そして７０〜７３℃に内温を維持したまま９０分間攪拌を続けて重合反応を行い、アミン含有酸溶解性樹脂溶液を得た。得られたアミン含有酸溶解性樹脂のアミン当量は３１５ｇ／モルであった。
【００３２】
次に得られたアミン含有酸溶解性樹脂溶液１００重量部、ＤＰＨＡ３０重量部、重合開始剤としてＴＸ及びＡＭをそれぞれ１重量部、着色顔料としてフタロシアニンブルー２．５重量部を３本ロールミルを用いて十分に混練分散して、酸現像型の感光性樹脂組成物Ａを得た。
【００３３】
合成例２
ＭＤＥＧＭＡ８００重量部、ＤＭＭＡ２００重量部、ＡＩＢＮ１５重量部、ＥＧＭＥ１０００重量部を冷却器、温度計、攪拌装置を取り付けた３リットルセパラブルフラスコに入れ、攪拌しながらマントルヒーターを用いて内温を７０℃まで上昇させた。そして７０〜７３℃に内温を維持したまま９０分間攪拌を続けて重合反応を行い、アミン含有酸溶解性樹脂溶液を得た。得られたアミン含有酸溶解性樹脂のアミン当量は７８５ｇ／モルであった。
【００３４】
次に得られたアミン含有酸溶解性樹脂溶液１００重量部、ＤＰＨＡとＴＭＰＴＡをそれぞれ２０重量部、重合開始剤としてＤＭＰＥ１重量部、着色顔料としてフタロシアニンブルー２．５重量部、さらにアクリル樹脂フィラー（綜研化学株式会社製、ＭＰ−３００）１５重量部を３本ロールミルを用いて十分に混練分散して、酸現像型の感光性樹脂組成物Ｂを得た。
【００３５】
合成例３
ＭＤＥＧＭＡ６００重量部、ＤＭＭＡ４００重量部、ＡＩＢＮ１５重量部、ＥＧＭＥ１０００重量部を冷却器、温度計、攪拌装置を取り付けた３リットルセパラブルフラスコに入れ、攪拌しながらマントルヒーターを用いて内温を７０℃まで上昇させた。そして７０〜７３℃に内温を維持したまま９０分間攪拌を続けて重合反応を行い、アミン含有酸溶解性樹脂溶液を得た。得られたアミン含有酸溶解性樹脂のアミン当量は３９２ｇ／モルであった。
【００３６】
次に得られたアミン含有酸溶解性樹脂溶液１００重量部、ＰＴＡ２０重量部、重合開始剤としてＴＸ及びＡＭをそれぞれ１重量部、着色顔料としてフタロシアニンブルー２．５重量部、さらにアクリル樹脂フィラー（綜研化学株式会社製、ＭＰ−３００）１０重量部を３本ロールミルを用いて十分に混練分散して、酸現像型の感光性樹脂組成物Ｃを得た。
【００３７】
合成例４
ＭＤＥＧＭＡ９９０重量部、ＤＭＭＡ１０重量部、ＡＩＢＮ１５重量部、ＥＧＭＥ１０００重量部を冷却器、温度計、攪拌装置を取り付けた３リットルセパラブルフラスコに入れ、攪拌しながらマントルヒーターを用いて内温を７０℃まで上昇させた。そして７０〜７３℃に内温を維持したまま９０分間攪拌を続けて重合反応を行い、アミン含有酸溶解性樹脂溶液を得た。得られたアミン含有酸溶解性樹脂のアミン当量は１５，０００ｇ／モルであった。
【００３８】
次に得られたアミン含有酸溶解性樹脂溶液１００重量部、ＤＰＨＡ３０重量部、重合開始剤としてＴＸ及びＡＭをそれぞれ１重量部、着色顔料としてフタロシアニンブルー２．５重量部を３本ロールミルを用いて十分に混練分散して、酸現像型の感光性樹脂組成物Ｄを得た。
【００３９】
合成例５
ＭＡＢＡ１５４．４ｇ（０．６モル）及びＤＡＰＥ８０．１ｇ（０．４モル）を５リットルのセパラブルフラスコ中で、攪拌しながら２，５６０ｇのＤＭＡｃに溶解させた。次にその溶液を氷浴で冷却し窒素気流中２１８．１ｇ（１モル）のＰＭＤＡを加えた。その後溶液を室温に戻し、３時間攪拌を続けて重合反応を行い、粘稠なポリアミック酸溶液Ｅを得た。得られたポリアミック酸溶液を市販の電解銅箔（三井金属鉱業株式会社製 ３ＥＣ−III）の光沢面に硬化後２５μｍの厚みになるように塗布し、１３０℃１０分間の熱処理を行い、さらに１６０℃、２００℃、２５０℃、３００℃、３５０℃で各２分の段階的な熱処理を行った後に、銅箔を塩化第２鉄水溶液を用いてエッチング除去して得られたポリイミドフィルムの線膨張係数は１．６×１０^-5／℃であった。
【００４０】
合成例６
ＤＡＰＥ２００．２ｇ（１モル）を５リットルのセパラブルフラスコ中で攪拌しながら２，６５０ｇのＤＭＡｃに溶解させた。次にその溶液を氷浴で冷却し、窒素気流中１６１．１ｇ（０．５モル）のＢＴＤＡ及び１０９．１ｇ（０．５モル）のＰＭＤＡを加えた。その後室温に戻し、３時間攪拌を続けて重合反応行い、粘稠なポリアミック酸溶液Ｆを得た。得られたポリアミック酸溶液を市販の電解銅箔（三井金属鉱業株式会社製、３ＥＣ−III）の光沢面に硬化後２５μｍの厚みになるように塗布し、１３０℃１０分間の熱処理を行い、さらに１６０℃、２００℃、２５０℃、３００℃、３５０℃で各２分の段階的な熱処理を行った後に、銅箔を塩化第２鉄水溶液を用いてエッチング除去して得られたポリイミドフィルムの線膨張係数は３．９×１０^-5／℃であった。
【００４１】
合成例７
ＰＤＡ７５．７ｇ（０．７モル）及びＤＡＰＥ６０．１ｇ（０．３モル）を５リットルのセパラブルフラスコ中で攪拌しながら２，０１０ｇのＤＭＡｃに溶解させた。次にその溶液を氷浴で冷却し、窒素気流中２１８．１ｇ（１モル）のＰＭＤＡを加えた。その後溶液を室温に戻し、３時間攪拌を続けて重合反応を行い、粘稠なポリアミック酸溶液Ｇを得た。得られたポリアミック酸溶液を市販の電解銅箔（三井金属鉱業株式会社製、３ＥＣ−III）の光沢面に硬化後２５μｍの厚みになるように塗布し、１３０℃１０分間の熱処理を行い、さらに１６０℃、２００℃、２５０℃、３００℃、３５０℃で各２分の段階的な熱処理を行った後に、銅箔を塩化第２鉄水溶液を用いてエッチング除去して得られたポリイミドフィルムの線膨張係数は２．３×１０^-5／℃であった。
【００４２】
実施例１
アプリケータを用いて合成例５で得られたポリアミック酸溶液Ｅを、厚さ２５μｍのステンレス箔（新日本製鐵株式会社製 ＳＵＳ３０４ Ｈ−ＴＡ材）上に硬化後１０μｍの厚みになるように塗布し、１１０℃で４分乾燥してポリアミック酸層を形成した後、その上に合成例１で得られた感光性樹脂組成物Ａを乾燥後１０μｍの厚みになるように塗布し、１１０℃で４分の乾燥を行い、さらにその上に厚み１６μｍの保護ＰＥＴフィルムを貼り付けて、ステンレス箔／ポリアミック酸／感光性樹脂／保護フィルムからなる積層体を得た。
【００４３】
次に、保護ＰＥＴフィルムと接触するようにフォトマスクを重ね合わせ、露光装置（ハイテック株式会社製、３０００ＮＥＬ）を用いて１００ｍＪ／ｃｍ² の露光を行った後、保護ＰＥＴフィルムを引き剥がし、簡易縦型シャワー装置を用いて２５℃の０．３％乳酸水溶液で８０秒間の現像処理ならびに３０秒間の水洗を行った。次いで、１２０℃で３分間の乾燥を行った後、１５℃の１０％水酸化カリウム水溶液で１５秒と４５℃の温水で２０秒の処理を行って、ポリアミック酸をエッチングした。
【００４４】
次に、３０℃の３０％乳酸水溶液で露光された部分の感光性樹脂を剥離除去し、さらに３０秒の水洗を行った後、熱風式オーブン中で１３０℃１０分間の熱処理を行い、さらに１６０℃、２００℃、２５０℃、３００℃、３５０℃で各２分の段階的な熱処理を行ってポリアミック酸のイミド化を完結させ、ステンレス箔上にパターニングされたポリイミド膜を得た。
【００４５】
得られたポリイミドパターンには欠け等の欠陥は認められず、加工された最小の穴直径及びエッチファクターは、それぞれ４０μｍ、１．５と優れたものであった。また、３００℃のはんだ浴に１分間浸漬したところ、膨れや剥がれの発生は認められなかった。
【００４６】
実施例２
バーコーターを用いて合成例６で得られたポリアミック酸溶液Ｆを、厚さ２０μｍのステンレス箔（新日本製鐵株式会社製 ＳＵＳ３０４ Ｈ−ＴＡ材）上に硬化後２μｍの厚みになるように塗布し１１０℃で２分乾燥した後、その上にアプリケータを用いて合成例５で得られたポリアミック酸溶液Ｅを硬化後８μｍの厚みになるように塗布し１１０℃で４分乾燥して２層構造のポリアミック酸層を形成した。次いで、合成例２で得られた感光性樹脂組成物Ｂを乾燥後１０μｍの厚みになるように塗布し１１０℃で４分の乾燥を行い、さらに厚み１６μｍの保護ＰＥＴフィルムを貼り付けて、ステンレス箔／ポリアミック酸Ｆ／ポリアミック酸Ｅ／感光性樹脂／保護フィルムからなる積層体を得た。
【００４７】
以下、実施例１と同様にポリイミドのパターニングを行ったところ、欠けなどの欠陥は特に認められず、加工精度も最小穴径５０μｍ、エッチファクター１．４と優れたものであった。また、３００℃のはんだ試験においても膨れや剥がれは認められなかった。
【００４８】
実施例３
アプリケータを用いて合成例７で得られたポリアミック酸溶液Ｇを、厚み２０μｍのステンレス箔（新日本製鐵株式会社製 ＳＵＳ３０４ Ｈ−ＴＡ材）上に硬化後７μｍの厚みになるように塗布し、１１０℃で４分乾燥してポリアミック酸層を形成した後、合成例３で得られた感光性樹脂組成物Ｃを乾燥後１０μｍの厚みになるように塗布し、１１０℃で４分の乾燥を行い、さらに厚み９μｍの保護ＰＥＴフィルムを貼り付けて、ステンレス箔／ポリアミック酸／感光性樹脂／保護フィルムからなる積層体を得た。
【００４９】
以下、１５℃の１０％水酸化カリウムの処理時間を１５秒から１２秒に変更した以外は実施例１と同様にポリイミドのパターニングを行った。得られたポリイミドパターンには欠けなどの欠陥は特に認められず、加工精度も最小穴径４０μｍ、エッチファクター１．６と優れたものであった。また、３００℃のはんだ試験においても膨れや剥がれは認められなかった。
【００５０】
実施例４
バーコータを用いて合成例６で得られたポリアミック酸溶液Ｆを、厚み１８μｍの銅合金箔（オーリンソマーズ社製 Ｃ７０２５ ＴＭ−０３）の粗面上に、硬化後５μｍの厚みになるように塗布し１１０℃で２分の乾燥を行った後、その上にアプリケータを用いて合成例５で得られたポリアミック酸溶液Ｅを、硬化後２０μｍの厚みになるように塗布し１３０℃で４分の乾燥を行って２層構造のポリアミック酸層を形成した。次いで、合成例１で得られた感光性樹脂組成物Ａを乾燥後２０μｍの厚みになるように塗布し１１０℃で４分の乾燥を行い、さらに厚み１６μｍの保護ＰＥＴフィルムを貼り付けて、銅合金箔／ポリアミック酸Ｆ／ポリアミック酸Ｅ／感光性樹脂／保護フィルムからなる積層体を得た。
【００５１】
次に、保護ＰＥＴフィルムと接触するようにフォトマスクを重ね合わせ、露光装置（ハイテック株式会社製、３０００ＮＥＬ）を用いて１００ｍＪ／ｃｍ² の露光を行った後、保護ＰＥＴフィルムを引き剥がし、簡易縦型シャワー装置を用いて２５℃の０．３％乳酸水溶液で８０秒間の現像処理と３０秒間の水洗を行った。次いで、１２０℃で３分間の乾燥を行った後、４５℃の１０％水酸化カリウム水溶液で２５秒と４５℃の温水で３０秒の処理を行って、ポリアミック酸をエッチングした。
【００５２】
次に、３０℃の３０％乳酸水溶液で露光された部分の感光性樹脂を剥離除去し、さらに３０秒の水洗を行った後、熱風式オーブン中で１３０℃１０分間の熱処理を行い、さらに１６０℃、２００℃、２５０℃、３００℃、３５０℃で各２分の段階的な熱処理を行ってポリアミック酸のイミド化を完結させ、銅合金箔上にパターニングされたポリイミド膜を得た。
【００５３】
得られたポリイミドパターンには欠けなどの欠陥は認められず、加工された最小の穴直径及びエッチファクターは、それぞれ７０μｍ、１．１と優れたものであった。また、３００℃のはんだ浴に１分間浸漬したところ、膨れや剥がれの発生は認められなかった。
【００５４】
比較例１
バーコーターを用いて合成例６で得られたポリアミック酸溶液Ｆを、厚さ２０μｍのステンレス箔（新日本製鐵株式会社製 ＳＵＳ３０４ Ｈ−ＴＡ材）上に硬化後２μｍの厚みになるように塗布し１１０℃で２分乾燥した後、その上にアプリケータを用いて合成例５で得られたポリアミック酸溶液Ｅを硬化後８μｍの厚みになるように塗布し１１０℃で４分乾燥して２層構造のポリアミック酸層を形成した。次いで、合成例４で得られた感光性樹脂組成物Ｄを乾燥後１０μｍの厚みになるように塗布し１１０℃で４分の乾燥を行い、さらに厚み１６μｍの保護ＰＥＴフィルムを貼り付けて、ステンレス箔／ポリアミック酸Ｆ／ポリアミック酸Ｅ／感光性樹脂／保護フィルムからなる積層体を得た。
【００５５】
次に、得られた積層体を用いて実施例１と同様に行ったところ、感光性樹脂に用いているアミン含有酸溶解性樹脂のアミン当量が１５，０００と大きかったため、酸による現像を行うことができず、その結果ポリイミドのパターニングには至らなかった。
【００５６】
【発明の効果】
本発明の積層体を用いることにより、水系の薬液による簡易なプロセスで、耐熱性等の特性に優れた高精度のポリイミドパターンを金属箔上に形成することが可能であり、配線付のＨＤＤサスペンションなどの用途に極めて好適である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a laminate suitable for manufacturing HDD suspensions and the like.
[0002]
[Prior art]
HDD (Hard Disk Drive) suspensions are manufactured by etching a metal foil with spring properties such as stainless steel. After mounting a magnetic head such as a thin film head or MR head on the tip of the suspension, It is mounted by wire bonding. In recent years, active efforts have been made to reduce the size, increase the density, and increase the capacity, and accordingly, it is essential to lower the flying height of the slider on which the magnetic head is directly mounted. From this point of view, the conventional gold wire has been a hindrance to low flying due to the influence of air resistance and rigidity. In addition, such wire bonding using a gold wire has a problem that it is difficult to automate the gold wire connecting process to the magnetic head.
[0003]
As a method for solving such problems associated with gold wire wire bonding, JP-A-8-45,213 discloses a circuit formation after patterning an insulating layer such as polyimide on a spring metal such as stainless steel. A suspension manufacturing method with wiring for manufacturing a suspension has been proposed. In particular, a method for laminating a non-photosensitive polyimide precursor and a photosensitive resist on a spring metal for polyimide patterning, developing the photosensitive resist, and then etching the polyimide precursor with alkali is disclosed. However, although it describes that the photosensitive resist is an acid developing type, it does not mention the specific structure or the like at all.
[0004]
[Problems to be solved by the invention]
Accordingly, an object of the present invention is to provide a laminate capable of forming a highly accurate polyimide pattern on a metal foil, which is suitable for manufacturing HDD suspensions and the like.
[0005]
[Means for Solving the Problems]
  That is, the present invention is a laminate having a polyamic acid layer and an acid-developable photosensitive resin layer formed on a metal foil, and the acid-developable photosensitive resin layer contains the following components as essential components. It is the laminated body characterized by this.
(1) An amine-containing acid-soluble resin having an amine equivalent of 100 to 10,000
(2) Monomer having two or more ethylenically unsaturated bonds in one molecule
(3) Photopolymerization initiator
Here, the amine-containing acid-soluble resin is a resin represented by the following formula (1), and the monomer having two or more ethylenically unsaturated bonds in one molecule is a polyfunctional acrylate or a polyfunctional methacrylate. It is.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Any metal foil can be used as the metal foil used in the present invention. However, when the laminate is applied to an HDD suspension, one having a certain degree of springiness is preferable. Examples of the metal having a spring property include stainless steel, beryllium copper, and highly elastic metals such as C7025 (manufactured by Olin Somers), and stainless steel is more preferable. In particular, stainless steel is preferably subjected to tension annealing at a temperature of 300 ° C. or higher.
[0007]
Moreover, as a polyamic acid used for this invention, the thing of arbitrary structures can be used. Usually, a polyamic acid can be synthesized by reacting a diamine compound and an acid anhydride compound in a polar solvent at a temperature of 0 to 200 ° C., preferably 0 to 100 ° C.
[0008]
Examples of the diamine compound include p-phenylenediamine, m-phenylenediamine, 2′-methoxy-4,4′-diaminobenzanilide, diaminodiphenyl ether, diaminotoluene, diaminodiphenylmethane, bis [(aminophenoxy) phenyl] propane, Examples include diaminodiphenylsulfone, diaminobenzanilide, diaminobenzoate, bisaminophenoxybenzene, aminophenoxybiphenyl, bis [(aminophenoxy) phenyl] sulfone, and the like.
[0009]
Examples of the acid anhydride include pyromellitic dianhydride, biphenyl tetracarboxylic dianhydride, benzophenone tetracarboxylic dianhydride, diphenyl sulfone tetracarboxylic dianhydride, diphenyl ether tetracarboxylic dianhydride, and naphthalene. Examples thereof include tetracarboxylic dianhydride, cyclobutane tetracarboxylic dianhydride, ethylene glycol bistrimellitate dianhydride, and trimellitic anhydride.
[0010]
Examples of polar solvents used in the synthesis reaction include N-methylpyrrolidone, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, dimethyl sulfate, sulfolane, butyrolactone, cresol, phenol, halogenated phenol, cyclohexanone, dioxane, tetrahydrofuran, and diglyme. Can be mentioned.
[0011]
The thickness of the polyamic acid layer used in the laminate of the present invention is 2 to 100 μm, preferably 5 to 50 μm. When the thickness of the polyamic acid is less than 2 μm, the strength of the finally obtained polyimide coating film is lowered. When the thickness is more than 100 μm, the formation of the coating film becomes difficult and the pattern accuracy of the polyimide is lowered.
[0012]
Usually, since the laminated body of this invention finally forms the patterned polyimide layer on base materials, such as a metal, it is important not to curl. Therefore, the polyamic acid is 1.0 × 10 after curing.^-Five~ 2.5 × 10^-FiveThose capable of giving a polyimide having a linear expansion coefficient of / ° C are preferred. More preferably, it is a polyamic acid containing 40% by weight or more of a structural unit represented by the following general formula (3).
[Formula 4]

(Wherein R₁~ R₈Represents the same or different hydrogen, halogen, alkyl group or alkoxy group)
The polyamic acid layer may be a polyamic acid layer having two or more different structures, and a coupling agent, an antioxidant, or the like may be added for the purpose of improving adhesiveness.
[0013]
Next, the photosensitive resin used in the laminate of the present invention is an acid developing type photosensitive resin containing the following components as essential components.
(1) An amine-containing acid-soluble resin having an amine equivalent of 100 to 10,000
(2) Monomer having two or more ethylenically unsaturated bonds in one molecule
(3) Photopolymerization initiator
[0014]
The amine-containing acid-soluble resin referred to here is a resin containing an amine in its structure, and its weight average molecular weight is preferably 100 to 1,000,000, more preferably 1,000 to 500,000. Is. Further, the amine contained may be any primary, secondary or tertiary amine. The amine equivalent defined by the molecular weight per mole of amine in the amine-containing acid-soluble resin is 100 to 10,000, preferably 200 to 2,000. If the amine equivalent is less than 100, the development rate of the photosensitive resin by the acid becomes too high, and the control thereof is difficult, and the problem of swelling of the photosensitive resin in the development process is likely to occur. On the other hand, if the amine equivalent is greater than 10,000, it is difficult to perform development with an acid.
[0015]
A preferred amine-containing acid-soluble resin used in the laminate of the present invention is a resin represented by the following general formula (1).
[Chemical formula 5]

(In the formula, m and n represent the molar ratio of each component, and m + n = 100 and m = 1 to 99. R₁Is any divalent organic residue, R₂And R_ThreeRepresents hydrogen or any monovalent organic residue, R_Four~ R₆Represents the same or different hydrogen, halogen or monovalent organic residue, R₇~ R_TenRepresents a monovalent organic residue containing no hydrogen, halogen or amine, which may be the same or different)
[0016]
A more preferred amine-containing acid-soluble resin is a resin represented by the following general formula (2).
[Chemical 6]

(In the formula, m and n represent the molar ratio of each component, and m + n = 100 and m = 1 to 99. R₁And R₂Represents hydrogen or a methyl group, R_ThreeRepresents any divalent organic residue, R_FourAnd R_FiveRepresents hydrogen or an alkyl group, R₆Represents any monovalent organic residue containing no amine)
[0017]
Such an amine-containing acid-soluble resin is a copolymer resin composed of an amine-containing structural unit and an amine-free structural unit. Examples of the monomer constituting the amine-containing structural unit include amino such as 2- (dimethylamino) ethyl methacrylate, 2- (diethylamino) ethyl methacrylate, 2- (dimethylamino) ethyl acrylate, and 2- (diethylamino) ethyl acrylate. One type or two or more types of monomers selected from group-containing methacrylates (acrylates) may be mentioned. Examples of the monomer constituting the amine-free structural unit include methyl methacrylate, ethyl methacrylate, butyl methacrylate, isobutyl methacrylate, lauryl methacrylate, methyl acrylate, ethyl acrylate, n-decyl methacrylate, 2-ethylhexyl methacrylate, and isodecyl. In addition to methacrylates such as methacrylates and hydroxyalkyl methacrylates such as hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxyethyl acrylate, and hydroxypropyl acrylate, acrylonitrile, styrene, hydroxystyrene, vinyl acetate, etc. 1 type or 2 types or more of the obtained monomer is mentioned.
[0018]
The second essential component in the photosensitive resin is a monomer having two or more ethylenically unsaturated bonds in one molecule. The monomer here is a compound having two or more ethylenically unsaturated bonds having an arbitrary substituent or adjacent group in one molecule. Examples of such monomers include polyfunctional acrylates, polyfunctional methacrylates, polyfunctional allyl compounds, polyfunctional vinyl ethers, and the like, and polyfunctional acrylates or polyfunctional methacrylates are preferable from the viewpoint of reaction rate. In addition, polyfunctional here means that the number of functional groups is 2 or more.
[0019]
Specific examples of polyfunctional acrylates include triethylene glycol diacrylate, polyethylene glycol diacrylate, neopentyl glycol diacrylate, hexanediol diacrylate, dimethylol-tricyclodecane diacrylate, dimethylol-propane triacrylate, pentaerythritol hexaacrylate. And dipentaerythritol hexaacrylate or a reaction product of a bifunctional or higher functional epoxy compound with acrylic acid. Polyfunctional methacrylates include ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, butanediol dimethacrylate, hexanediol dimethacrylate, trimethylolpropane trimethacrylate, triethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, and bifunctional or more epoxy. Examples include a reaction product of a compound and methacrylic acid. By using such a monomer having two or more ethylenically unsaturated bonds in one molecule, the active species such as radicals and acids generated from the photopolymerization initiator by light irradiation may cause ethylenically unsaturated bonds. It reacts, thereby making the photosensitive resin insoluble in acid.
[0020]
Furthermore, the third essential component in the photosensitive resin is a photopolymerization initiator. The photopolymerization initiator used in the present invention includes a radical generation type and an acid generation type, and can be selected depending on the type of monomer having two or more ethylenically unsaturated bonds in one molecule used in combination. . When acrylate or methacrylate is used as a monomer having two or more ethylenically unsaturated bonds in one molecule, a radical-generating photopolymerization initiator is preferably selected.
[0021]
Specific examples of the photopolymerization initiator include acetophenones such as acetophenone, 2,2-diethoxyacetophenone, p-dimethylacetophenone, p-dimethylaminopropiophenone, dichloroacetophenone, trichloroacetophenone and p-tert-butylacetophenone. Benzophenones such as benzophenone, 2-chlorobenzophenone, p, p'-bisdimethylaminobenzophenone, benzoin ethers such as benzyl, benzoin, benzoin methyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzyldimethyl ketal, thioxanthone, 2 -Sulfur compounds such as chlorothioxanthone, 2,4-diethylthioxanthone, 2-methylthioxanthone, 2-isopropylthioxanthone Anthraquinones such as 2-ethylanthraquinone, octamethylanthraquinone, 1,2-benzanthraquinone, 2,3-diphenylanthraquinone, organic peroxides such as benzoyl peroxide, cumene peroxide, 2-mercaptobenzimidazole, 2-mercapto Examples thereof include thiol compounds such as benzoxazole and 2-mercaptobenzothiazole, and azobisisobutylnitrile.
[0022]
These photopolymerization initiators may be used alone or in combination of two or more. In addition, a compound that does not act as a photopolymerization initiator per se, but that can increase the ability of the photopolymerization initiator by using it in combination with the above-mentioned compound can also be added. Examples of such compounds include tertiary amines such as triethanolamine which are effective when used in combination with benzophenone.
[0023]
In addition to the above essential components, the photosensitive resin components used in the present invention include fillers, color formers, ultraviolet absorbers, polymerizations for the purpose of adjusting fluidity, tackiness, color developability, storage stability, and the like. Inhibitors, pigments, dyes and the like may be added.
[0024]
The production of the laminate of the present invention is not particularly limited and any method can be adopted. However, the following method is simple and preferable from the viewpoint of productivity. First, after applying a polyamic acid solution on a metal foil, it is dried to form a polyamic acid layer. At that time, the drying temperature is preferably 200 ° C. or lower in order to prevent side reactions such as imidization reaction. Next, the photosensitive resin solution is applied on the polyamic acid layer and dried to form a photosensitive resin layer. The drying temperature at that time is preferably 200 ° C. or lower in order to prevent a thermal crosslinking reaction of the photosensitive resin.
[0025]
In the laminate of the present invention, a protective layer can be further formed on the surface of the photosensitive resin or a protective film can be attached in order to prevent foreign matter contamination and mechanical damage.
[0026]
Using the laminate of the present invention, polyimide can be patterned on a metal foil by the following steps.
(1) A step of irradiating a necessary portion of the photosensitive resin with visible light or ultraviolet rays through a photomask.
(2) Development process of photosensitive resin
(3) Polyamic acid etching process
(4) Photoresin peeling process
(5) Imidization process of polyamic acid
[0027]
By such a process, a polyimide layer patterned with high accuracy can be formed. Furthermore, when the laminate of the present invention is applied to a suspension with wiring as disclosed in Japanese Patent Application Laid-Open No. 8-45,213, a conductor is formed on polyimide by sputtering or plating after the above steps. Is possible.
[0028]
By using the laminate of the present invention, it is possible to perform highly precise polyimide patterning excellent in heat resistance and reliability on a metal foil, and application to various uses is possible. In particular, when applied to an HDD suspension, it is excellent in heat resistance and reliability, as well as low outgas properties and the like, which is extremely suitable.
[0029]
【Example】
Hereinafter, the present invention will be specifically described based on examples. In addition, the measurement of the linear expansion coefficient and amine equivalent in an Example is as follows.
(1) For the measurement of the expansion coefficient, a thermomechanical analyzer (manufactured by Seiko Denshi Co., Ltd., TMA-100) was used. The temperature was raised to 250 ° C. and held at that temperature for 20 minutes, and then at a rate of 10 ° C./min. It cooled and calculated | required the average linear expansion coefficient from 240 degreeC to 100 degreeC.
(2) Regarding the measurement of the amine equivalent of the amine-containing acid-soluble resin, first, the amine-containing acid-soluble resin solution is weighed so that the amount of the amine-containing acid-soluble resin is 1 g, and the weight ratio of ethyl cellosolve to water. Was dissolved in a 1: 1 mixed solution and diluted exactly to 100 ml. Next, 25 ml of the resin solution was titrated with 0.02 mol / l lactic acid aqueous solution using an automatic titrator (Hiranuma Sangyo Co., Ltd., COMMITE-500). It calculated using the following formula from the amount of lactic acid aqueous solution Vml required so far.
Amine equivalent (g / mol) = 1 (g) × 25 (ml) / 100 (ml) /0.02 (mol / l) / 1000 / V (ml)
(3) About processing precision, the minimum hole diameter of the polyimide which has a favorable shape was visually determined using the photomask which has a circular pattern from which a diameter is a 10 micrometer step. As another method, processing was performed using a photomask in which lines having a width of 100 μm and gaps having a width of 100 μm were alternately patterned, and the polyimide layer cross section was observed to calculate an etch factor. The following calculation formula was used for the etch factor (f).
f = 2d / (t₁-T₂)
(Where t₁Is the length of the bottom of the trapezoid of the polyimide pattern cross section, t₂Is the length of the upper base of the trapezoidal cross section, and d is the thickness of the polyimide layer)
[0030]
Abbreviations used in Examples and the like are as follows.
MMA: Methyl methacrylate
HOMA: 2-hydroxyethyl methacrylate
DMMA: 2- (dimethylamino) ethyl methacrylate
MDEGMA: Methoxydiethylene glycol methacrylate
AIBN: Azobisisobutyronitrile
EGME: Ethylene glycol monoethyl ether
DPHA: Dipentaerythritol hexaacrylate
PTA: Pentaerythritol tetraacrylate
TMPTA: Trimethylolpropane triacrylate
TX: 2,4-diethylthioxanthone
AM: p-dimethylaminobenzoic acid isoamyl ester
DMPE: 2,2-dimethoxy-1,2-diphenylethane-1-one
MABA: 4,4'-diamino-2'-methoxybenzanilide
DAPE: 4,4'-diaminodiphenyl ether
PDA: p-phenylenediamine
PMDA: pyromellitic dianhydride
BTDA: 3,4,3 ', 4'-benzophenone tetracarboxylic dianhydride
DMAc: N, N-dimethylacetamide
[0031]
Synthesis example 1
MMA 400 parts by weight, HOMA 100 parts by weight, DMMA 500 parts by weight, AIBN 15 parts by weight, EGME 1000 parts by weight are put into a 3 liter separable flask equipped with a condenser, thermometer and stirrer, and the internal temperature is adjusted using a mantle heater while stirring. The temperature was raised to 70 ° C. And stirring was continued for 90 minutes, maintaining internal temperature at 70-73 degreeC, and the polymerization reaction was performed, and the amine containing acid-soluble resin solution was obtained. The amine equivalent of the obtained amine-containing acid-soluble resin was 315 g / mol.
[0032]
Next, 100 parts by weight of the obtained amine-containing acid-soluble resin solution, 30 parts by weight of DPHA, 1 part by weight of TX and AM as polymerization initiators, and 2.5 parts by weight of phthalocyanine blue as a color pigment using a three-roll mill. By sufficiently kneading and dispersing, an acid developing type photosensitive resin composition A was obtained.
[0033]
Synthesis example 2
Place 800 parts by weight of MDEGMA, 200 parts by weight of DMMA, 15 parts by weight of AIBN, and 1000 parts by weight of EGME in a 3 liter separable flask equipped with a condenser, thermometer, and stirrer, and increase the internal temperature to 70 ° C using a mantle heater while stirring. I let you. And stirring was continued for 90 minutes, maintaining internal temperature at 70-73 degreeC, and the polymerization reaction was performed, and the amine containing acid-soluble resin solution was obtained. The amine equivalent of the obtained amine-containing acid-soluble resin was 785 g / mol.
[0034]
Next, 100 parts by weight of the resulting amine-containing acid-soluble resin solution, 20 parts by weight of DPHA and TMPTA, 1 part by weight of DMPE as a polymerization initiator, 2.5 parts by weight of phthalocyanine blue as a color pigment, and an acrylic resin filler (Sanken) Chemical Co., Ltd., MP-300) 15 parts by weight was sufficiently kneaded and dispersed using a three roll mill to obtain an acid developing type photosensitive resin composition B.
[0035]
Synthesis example 3
Place 600 parts by weight of MDEGMA, 400 parts by weight of DMMA, 15 parts by weight of AIBN, and 1000 parts by weight of EGME into a 3 liter separable flask equipped with a condenser, thermometer, and stirrer, and increase the internal temperature to 70 ° C using a mantle heater while stirring. I let you. And stirring was continued for 90 minutes, maintaining internal temperature at 70-73 degreeC, and the polymerization reaction was performed, and the amine containing acid-soluble resin solution was obtained. The amine equivalent of the obtained amine-containing acid-soluble resin was 392 g / mol.
[0036]
Next, 100 parts by weight of the resulting amine-containing acid-soluble resin solution, 20 parts by weight of PTA, 1 part by weight of TX and AM as polymerization initiators, 2.5 parts by weight of phthalocyanine blue as color pigments, and an acrylic resin filler (Kohken) Chemical Co., Ltd., MP-300) 10 parts by weight was sufficiently kneaded and dispersed using a three roll mill to obtain an acid developing type photosensitive resin composition C.
[0037]
Synthesis example 4
Place 990 parts by weight of MDEGMA, 10 parts by weight of DMMA, 15 parts by weight of AIBN, and 1000 parts by weight of EGME into a 3 liter separable flask equipped with a condenser, thermometer, and stirrer, and increase the internal temperature to 70 ° C using a mantle heater while stirring. I let you. And stirring was continued for 90 minutes, maintaining internal temperature at 70-73 degreeC, and the polymerization reaction was performed, and the amine containing acid-soluble resin solution was obtained. The amine equivalent of the obtained amine-containing acid-soluble resin was 15,000 g / mol.
[0038]
Next, 100 parts by weight of the obtained amine-containing acid-soluble resin solution, 30 parts by weight of DPHA, 1 part by weight of TX and AM as polymerization initiators, and 2.5 parts by weight of phthalocyanine blue as a color pigment using a three-roll mill. By sufficiently kneading and dispersing, an acid developing type photosensitive resin composition D was obtained.
[0039]
Synthesis example 5
MABA 154.4 g (0.6 mol) and DAPE 80.1 g (0.4 mol) were dissolved in 2,560 g DMAc with stirring in a 5 liter separable flask. The solution was then cooled in an ice bath and 218.1 g (1 mole) of PMDA was added in a nitrogen stream. Thereafter, the solution was returned to room temperature and stirred for 3 hours to conduct a polymerization reaction, thereby obtaining a viscous polyamic acid solution E. The obtained polyamic acid solution was applied to a glossy surface of a commercially available electrolytic copper foil (3EC-III, manufactured by Mitsui Mining & Smelting Co., Ltd.) so as to have a thickness of 25 μm, heat-treated at 130 ° C. for 10 minutes, and further 160 Linear expansion of polyimide film obtained by performing stepwise heat treatment at 2 ° C., 200 ° C., 250 ° C., 300 ° C., 350 ° C. for 2 minutes each and then etching away copper foil with ferric chloride aqueous solution The coefficient is 1.6 × 10^-Five/ ° C.
[0040]
Synthesis Example 6
200.2 g (1 mole) of DAPE was dissolved in 2,650 g of DMAc with stirring in a 5 liter separable flask. The solution was then cooled in an ice bath and 161.1 g (0.5 mol) of BTDA and 109.1 g (0.5 mol) of PMDA were added in a nitrogen stream. Thereafter, the temperature was returned to room temperature and stirring was continued for 3 hours to conduct a polymerization reaction, whereby a viscous polyamic acid solution F was obtained. The obtained polyamic acid solution was applied to a glossy surface of a commercially available electrolytic copper foil (manufactured by Mitsui Kinzoku Mining Co., Ltd., 3EC-III) so as to have a thickness of 25 μm, followed by heat treatment at 130 ° C. for 10 minutes, A polyimide film line obtained by performing stepwise heat treatment at 160 ° C., 200 ° C., 250 ° C., 300 ° C., and 350 ° C. for 2 minutes each, and then etching and removing the copper foil using a ferric chloride aqueous solution. The expansion coefficient is 3.9 × 10^-Five/ ° C.
[0041]
Synthesis example 7
75.7 g (0.7 mol) PDA and 60.1 g (0.3 mol) DAPE were dissolved in 2,010 g DMAc with stirring in a 5 liter separable flask. The solution was then cooled in an ice bath and 218.1 g (1 mole) of PMDA was added in a nitrogen stream. Thereafter, the solution was returned to room temperature and stirred for 3 hours to conduct a polymerization reaction, whereby a viscous polyamic acid solution G was obtained. The obtained polyamic acid solution was applied to a glossy surface of a commercially available electrolytic copper foil (manufactured by Mitsui Kinzoku Mining Co., Ltd., 3EC-III) so as to have a thickness of 25 μm, followed by heat treatment at 130 ° C. for 10 minutes, A polyimide film line obtained by performing stepwise heat treatment at 160 ° C., 200 ° C., 250 ° C., 300 ° C., and 350 ° C. for 2 minutes each, and then etching and removing the copper foil using a ferric chloride aqueous solution. The expansion coefficient is 2.3 × 10^-Five/ ° C.
[0042]
Example 1
Application of polyamic acid solution E obtained in Synthesis Example 5 using an applicator on a stainless steel foil having a thickness of 25 μm (SUS304 H-TA material manufactured by Nippon Steel Corp.) to a thickness of 10 μm after curing. Then, after drying at 110 ° C. for 4 minutes to form a polyamic acid layer, the photosensitive resin composition A obtained in Synthesis Example 1 was applied thereon to a thickness of 10 μm after drying, and at 110 ° C. After drying for 4 minutes, a protective PET film having a thickness of 16 μm was further adhered thereon to obtain a laminate composed of stainless steel foil / polyamic acid / photosensitive resin / protective film.
[0043]
Next, a photomask is overlaid so as to come into contact with the protective PET film, and 100 mJ / cm using an exposure apparatus (3000NEL manufactured by Hitec Corporation)²After the exposure, the protective PET film was peeled off, and a development process for 80 seconds and a 30 second water wash were performed with a 0.3% lactic acid aqueous solution at 25 ° C. using a simple vertical shower apparatus. Next, after drying at 120 ° C. for 3 minutes, the polyamic acid was etched by treatment with 15% 10% aqueous potassium hydroxide solution for 15 seconds and warm water at 45 ° C. for 20 seconds.
[0044]
Next, the exposed photosensitive resin was peeled and removed with a 30% aqueous lactic acid solution at 30 ° C., washed with water for 30 seconds, and then heat-treated in a hot air oven at 130 ° C. for 10 minutes, and further 160 Stepwise heat treatment was performed at 2 ° C., 200 ° C., 250 ° C., 300 ° C., and 350 ° C. for 2 minutes to complete imidization of the polyamic acid, and a polyimide film patterned on the stainless steel foil was obtained.
[0045]
Defects such as chips were not observed in the obtained polyimide pattern, and the processed minimum hole diameter and etch factor were excellent at 40 μm and 1.5, respectively. Further, when immersed in a solder bath at 300 ° C. for 1 minute, no occurrence of swelling or peeling was observed.
[0046]
Example 2
Using a bar coater, the polyamic acid solution F obtained in Synthesis Example 6 was applied onto a 20 μm-thick stainless steel foil (SUS304 H-TA material manufactured by Nippon Steel Corp.) so as to have a thickness of 2 μm. After drying at 110 ° C. for 2 minutes, the polyamic acid solution E obtained in Synthesis Example 5 was applied thereon to a thickness of 8 μm using an applicator, and dried at 110 ° C. for 4 minutes. A polyamic acid layer having a layer structure was formed. Next, after drying, the photosensitive resin composition B obtained in Synthesis Example 2 was applied to a thickness of 10 μm, dried at 110 ° C. for 4 minutes, and further a protective PET film having a thickness of 16 μm was attached, and stainless steel was applied. A laminate comprising foil / polyamic acid F / polyamic acid E / photosensitive resin / protective film was obtained.
[0047]
Thereafter, polyimide was patterned in the same manner as in Example 1. As a result, defects such as chipping were not particularly observed, and the processing accuracy was excellent with a minimum hole diameter of 50 μm and an etch factor of 1.4. Also, no swelling or peeling was observed in the 300 ° C. solder test.
[0048]
Example 3
Apply the polyamic acid solution G obtained in Synthesis Example 7 using an applicator onto a 20 μm thick stainless steel foil (SUS304 H-TA material manufactured by Nippon Steel Co., Ltd.) so that the thickness is 7 μm after curing. After drying at 110 ° C. for 4 minutes to form a polyamic acid layer, the photosensitive resin composition C obtained in Synthesis Example 3 was applied to a thickness of 10 μm after drying, and dried at 110 ° C. for 4 minutes. Then, a protective PET film having a thickness of 9 μm was further attached to obtain a laminate composed of stainless steel foil / polyamic acid / photosensitive resin / protective film.
[0049]
Thereafter, polyimide was patterned in the same manner as in Example 1 except that the treatment time of 10% potassium hydroxide at 15 ° C. was changed from 15 seconds to 12 seconds. In the obtained polyimide pattern, defects such as chipping were not particularly recognized, and the processing accuracy was excellent with a minimum hole diameter of 40 μm and an etch factor of 1.6. Also, no swelling or peeling was observed in the 300 ° C. solder test.
[0050]
Example 4
Using a bar coater, the polyamic acid solution F obtained in Synthesis Example 6 was applied onto a rough surface of a copper alloy foil (C7025 TM-03, manufactured by Olin Somers) to a thickness of 5 μm after curing. After drying at 110 ° C. for 2 minutes, the polyamic acid solution E obtained in Synthesis Example 5 was applied thereon using an applicator so as to have a thickness of 20 μm after curing, and at 130 ° C. for 4 minutes. Drying was performed to form a polyamic acid layer having a two-layer structure. Next, after drying the photosensitive resin composition A obtained in Synthesis Example 1 so as to have a thickness of 20 μm, drying was performed at 110 ° C. for 4 minutes, and a protective PET film having a thickness of 16 μm was further attached, and copper A laminate comprising alloy foil / polyamic acid F / polyamic acid E / photosensitive resin / protective film was obtained.
[0051]
Next, a photomask is overlaid so as to come into contact with the protective PET film, and 100 mJ / cm using an exposure apparatus (3000NEL manufactured by Hitec Corporation)²After the exposure, the protective PET film was peeled off, and a development process for 80 seconds and a 30-second washing with a 0.3% lactic acid aqueous solution at 25 ° C. were performed using a simple vertical shower apparatus. Next, after drying at 120 ° C. for 3 minutes, the polyamic acid was etched by treating with 45% 10% aqueous potassium hydroxide solution for 25 seconds and 45 ° C. hot water for 30 seconds.
[0052]
Next, the exposed photosensitive resin was peeled and removed with a 30% aqueous lactic acid solution at 30 ° C., washed with water for 30 seconds, and then heat-treated in a hot air oven at 130 ° C. for 10 minutes, and further 160 Stepwise heat treatment was performed at 2 ° C., 200 ° C., 250 ° C., 300 ° C., and 350 ° C. for 2 minutes each to complete imidization of the polyamic acid, and a polyimide film patterned on the copper alloy foil was obtained.
[0053]
The obtained polyimide pattern showed no defects such as chipping, and the processed minimum hole diameter and etch factor were excellent at 70 μm and 1.1, respectively. Further, when immersed in a solder bath at 300 ° C. for 1 minute, no occurrence of swelling or peeling was observed.
[0054]
Comparative Example 1
Using a bar coater, the polyamic acid solution F obtained in Synthesis Example 6 was applied onto a 20 μm-thick stainless steel foil (SUS304 H-TA material manufactured by Nippon Steel Corp.) so as to have a thickness of 2 μm. After drying at 110 ° C. for 2 minutes, the polyamic acid solution E obtained in Synthesis Example 5 was applied thereon to a thickness of 8 μm using an applicator, and dried at 110 ° C. for 4 minutes. A polyamic acid layer having a layer structure was formed. Next, the photosensitive resin composition D obtained in Synthesis Example 4 was applied to a thickness of 10 μm after drying, dried at 110 ° C. for 4 minutes, and further a protective PET film having a thickness of 16 μm was attached, and stainless steel was applied. A laminate comprising foil / polyamic acid F / polyamic acid E / photosensitive resin / protective film was obtained.
[0055]
Next, when the obtained laminate was used in the same manner as in Example 1, the amine equivalent of the amine-containing acid-soluble resin used for the photosensitive resin was as large as 15,000. As a result, polyimide patterning was not achieved.
[0056]
【The invention's effect】
By using the laminate of the present invention, it is possible to form a highly accurate polyimide pattern with excellent characteristics such as heat resistance on a metal foil by a simple process using an aqueous chemical solution. It is extremely suitable for such applications.

Claims (5)

A laminate having a polyamic acid layer and an acid-developable photosensitive resin layer formed on a metal foil, wherein the acid-developable photosensitive resin layer contains the following components as essential components: body.
(1) An amine-containing acid-soluble resin represented by the following general formula (1) having an amine equivalent of 100 to 10,000

(In the formula, m and n represent the molar ratio of each component, and m + n = 100 and m = 1 to 99. R ₁ is an arbitrary divalent organic residue, and R ₂ and R ₃ are Represents hydrogen or any monovalent organic residue, R _{4 to} R ₆ represent hydrogen, halogen or monovalent organic residue which may be the same or different, and R _{7 to} R ₁₀ represent the same or different. Represents a monovalent organic residue containing no hydrogen, halogen or amine)
(2) Multifunctional acrylate or polyfunctional methacrylate (3) Photopolymerization initiator The laminate according to claim 1, wherein the metal foil is a stainless steel foil . The laminate according to claim 1, wherein the amine-containing acid-soluble resin is a resin represented by the following general formula (2).

(Wherein, m and n represent mole ratios of the respective components, m + n = 100, m = .R 1 and R ₂ is a 1 to 99 represents hydrogen or a methyl group, R ₃ is any divalent R ₄ and R ₅ represent hydrogen or an alkyl group, and R ₆ represents any monovalent organic residue containing no amine) The laminate according to any one of claims 1 to 3, wherein the polyamic acid contains 40% by weight or more of a structural unit represented by the following general formula (3) .

(Wherein R _{1 to} R ₈ represent the same or different hydrogen, halogen, alkyl group or alkoxy group) The laminate according to any one of claims 1 to 4, wherein the polyamic acid layer gives a polyimide having a coefficient of thermal expansion of 1.0 x ^{10-5 to} 2.5 x ^10-5 / ° C after curing.