JP3944971B2 - Photosensitive resin composition and photosensitive element using the same - Google Patents

Description

（式中、Ｒ₁、Ｒ₂及びＲ₃はＨ又はＣＨ₃であり、これらは同一であっても相違してもよい。また、Αは−ＣＨ ₂ ＣＨ ₂ −であり、Ｂは−ＣＨ（ＣＨ ₃ ）ＣＨ ₂ −又は−ＣＨ ₂ ＣＨ（ＣＨ ₃ ）−であり、ｍ₁、ｍ₂、ｍ₃、ｎ₁、ｎ₂及びｎ₃は、ｍ₁＋ｍ₂＋ｍ₃が６〜１０、ｎ₁＋ｎ₂＋ｎ₃が１５〜３６の範囲にある正の整数である。）
を５〜１００重量％を含有することを特徴とする感光性樹脂組成物に関する。
【００１３】
【化２】

（式中、Ｒ₁、Ｒ₂及びＲ₃はＨ又はＣＨ₃であり、これらは同一であっても相違してもよい。また、Α及びＢは−ＣＨ（ＣＨ₃）ＣＨ₂−若しくは−ＣＨ₂ＣＨ（ＣＨ₃）−又は−ＣＨ₂ＣＨ₂−であり、Α及びＢは相異なるものであり、ｍ₁、ｍ₂、ｍ₃、ｎ₁、ｎ₂及びｎ₃は、ｍ₁＋ｍ₂＋ｍ₃が６〜４５、ｎ₁＋ｎ₂＋ｎ₃が３〜４５の範囲にある正の整数である。）
を５〜７０重量％を含有することを特徴とする感光性樹脂組成物に関する。
【００１４】
また、本発明は、上記の感光性樹脂組成物を支持体上に塗布、乾燥してなる感光性エレメントに関する。
【００１５】
【発明の実施の形態】
本発明の感光性樹脂組成物及び感光性エレメントにおいて、（Ｃ）成分のエチレン性不飽和化合物として上記一般式（Ｉ）で示される化合物を光重合可能な不飽和化合物として用いると、硬化後のレジストが特にめっき工程において十分な耐性を示すとともに剥離工程において良好な剥離性を示し、硬化膜が柔軟性に富んでいるという特性を示す。
【００１６】
本発明に用いる（Ｉ）式で示される光重合可能な不飽和化合物において、エチレングリコール鎖のみである場合、剥離性をよくするために側鎖を長くすると親水性が増し膨潤が起こりやすく耐めっき性が損われる。またプロピレングリコールのみである場合は、同様に剥離性をよくするために側鎖を長くするとバインダーとの相溶性が悪くなり、均一な組成物とならず、相分離を起こしてしまう。
【００１７】
（Ａ）成分として用いられるカルボキシル基含有バインダーポリマーとしては、例えば、（メタ）アクリル酸アルキルエステル［（メタ）アクリル酸とはメタクリル酸及びアクリル酸を意味する。以下同じ。］と（メタ）アクリル酸とこれらと共重合しうるビニルモノマーとの共重合体等が挙げられる。これらの共重合体は、単独で又は２種以上組み合わせて用いることができる。
【００１８】
（メタ）アクリル酸アルキルエステルとしては、例えば、（メタ）アクリル酸メチルエステル、（メタ）アクリル酸エチルエステル、（メタ）アクリル酸ブチルエステル、（メタ）アクリル酸２−エチルヘキシルエステル等が挙げられる。
【００１９】
また、（メタ）アクリル酸アルキルエステルや（メタ）アクリル酸と共重合し得るビニルモノマーとしては、例えば、（メタ）アクリル酸テトラヒドロフルフリルエステル、（メタ）アクリル酸ジメチルアミノエチルエステル、（メタ）アクリル酸ジエチルアミノエチルエステル、メタクリル酸グリシジルエステル、２，２，２−トリフルオロエチル（メタ）アクリレート、２，２，３，３−テトラフルオロプロピル（メタ）アクリレート、アクリルアミド、ジアセトンアクリルアミド、スチレン、ビニルトルエン等が挙げられる。
【００２０】
本発明の（Ｂ）成分として用いられる光重合開始剤としては、例えば、ベンゾフェノン、Ｎ，Ｎ′−テトラメチル−４，４′−ジアミノベンゾフェノン（ミヒラーケトン）、Ｎ，Ｎ′−テトラエチル−４，４′−ジアミノベンゾフェノン、４−メトキシ−４′−ジアミノベンゾフェノン、２−エチルアントラキノン、フェナントレンキノン等の芳香族ケトン、ベンゾインメチルエーテル、ベンゾインエチルエーテル、ベンゾインフェニルエーテル等のベンゾインエーテル、メチルベンゾイン、エチルベンゾイン等のベンゾイン、ベンジルジメチルケタール等のベンジル誘導体、２−（ｏ−クロロフェニル）−４，５−ジフェニルイミダゾール二量体、２−（ｏ−クロロフェニル）−４，５−ジ（ｍ−メトキシフェニル）イミダゾール二量体、２−（ｏ−フルオロフェニル）−４，５−ジフェニルイミダゾール二量体、２−（ｏ−メトキシフェニル）−４，５−ジフェニルイミダゾール二量体、２，４−ジ−（ｐ−メトキシフェニル）−５−フェニルイミダゾール二量体、２−（２，４−ジメトキシフェニル）−４，５−ジフェニルイミダゾール二量体、２−（ｐ−メチルメルカプトフェニル）−４，５−ジフェニルイミダゾール二量体等の２，４，５−トリアリールイミダゾール二量体、９−フェニルアクリジン、１，７−ビス（９，９′−アクリジニル）ヘプタン等のアクリジン誘導体などが挙げられる。これらは、単独で又は２種以上を組み合わせて用いることができる。
【００２１】
本発明の（Ｃ）成分として用いられる少なくとも１つの重合可能なエチレン性不飽和結合を有する光重合性化合物のうち、必須成分として含まれる一般式（Ｉ）で示されるエチレン性不飽和化合物としては、ｍ₁、ｍ₂、ｍ₃、ｎ₁、ｎ₂及びｎ₃が正の整数であり、ｍ₁＋ｍ₂＋ｍ₃が６〜４５（好ましくは９〜２４）、ｎ₁＋ｎ₂＋ｎ₃が３〜４５（好ましくは６〜２４）の範囲内にあるものであれば、特に制限はないが、構造中に含有されるプロピレングリコール基の総数がエチレングリコール基の総数より大きいことが好ましく、エチレングリコール基の総数が１０以下であることがより好ましい。一般式（Ｉ）で示されるエチレン性不飽和化合物において、ｍ₁＋ｍ₂＋ｍ₃が６未満であると硬化後の皮膜がもろくなり、４５を超えると感度、密着性、強度が劣り、ｎ₁＋ｎ₂＋ｎ₃が３未満であると、硬化後の皮膜がもろくなり、４５を超えると感度、密着性、強度が劣る。
【００２２】
また、（Ｃ）成分として用いられる、前記必須成分の化合物以外の少なくとも１つの重合可能なエチレン性不飽和結合を有する光重合性化合物としては、例えば、ポリエチレングリコールジ（メタ）アクリレート（エチレン基の数が２〜１４のもの）、トリメチロールプロパンジ（メタ）アクリレート、トリメチロールプロパントリ（メタ）アクリレート、テトラメチロールメタントリ（メタ）アクリレート、テトラメチロールメタンテトラ（メタ）アクリレート、ポリプロピレングリコールジ（メタ）アクリレート（プロピレン基の数が２〜１４のもの）、ジペンタエリスリトールペンタ（メタ）アクリレート、ジペンタエリスリトールヘキサ（メタ）アクリレート等の多価アルコールにα，β−不飽和カルボン酸を反応させて得られる化合物、ビスフェノールΑジオキシエチレンジ（メタ）アクリレート、ビスフェノールΑトリオキシエチレンジ（メタ）アクリレート、ビスフェノールΑデカオキシエチレンジ（メタ）アクリレート等のビスフェノールΑポリオキシエチレンジ（メタ）アクリレート、トリメチロールプロパントリグリシジルエーテルトリアクリレート、ビスフェノールΑジグリシジルエーテルアクリレート等のグリシジル基含有化合物にα，β−不飽和カルボン酸を付加して得られる化合物、無水フタル酸等の多価カルボン酸とβ−ヒドロキシエチル（メタ）アクリレート等の水酸基及びエチレン性不飽和基を有する化合物とのエステル化物、（メタ）アクリル酸メチルエステル、（メタ）アクリル酸エチルエステル、（メタ）アクリル酸ブチルエステル、（メタ）アクリル酸２−エチルヘキシルエステル等の（メタ）アクリル酸のアルキルエスエル、トリメチロールプロパンエトキシトリアクリレートなどが挙げられる。
【００２３】
本発明において、（Ａ）成分の配合量は、（Α）成分及び（Ｃ）成分の合計量１００重量部に対して４０〜８０重量部の範囲とすることが好ましい。より好ましくは４５〜７０重量部の範囲とする。４０重量部未満では光硬化物が脆くなり易く、また感光性エレメントとして用いた場合、塗膜性に劣る傾向があり、８０重量部を超えると感度が不十分となる傾向がある。
【００２４】
また、（Ｃ）成分の配合量は、（Ａ）成分及び（Ｃ）成分の合計量１００重量部に対し、２０〜６０重量部の範囲とすることが好ましい。より好ましくは３０〜５５重量部の範囲とする。この配合量が２０重量部未満では感度が不十分となる傾向があり、６０重量部を超えると光硬化物が脆くなる傾向がある。
【００２５】
なお、（Ｃ）成分中の必須成分である一般式（Ｉ）で示されるエチレン性不飽和化合物の配合量は、（Ｃ）成分中５〜７０重量％、好ましくは１０〜５０％の範囲とする。この配合量が５重量％未満では剥離時間が長くなり、７０重量％を超えるとテント強度が弱くなる。
【００２６】
（Ｂ）成分の光重合開始剤の配合量は、（Ａ）成分及び（Ｃ）成分の合計量１００重量部に対して０．１〜２０重量部の範囲とすることが好ましい。より好ましくは０．２〜１０重量部の範囲とする。０．１重量部未満では感度が不十分となる傾向があり、２０重量部を超えると露光の際に組成物の表面での吸収が増大して内部の光硬化が不十分となる傾向がある。
【００２７】
本発明の感光性樹脂組成物には、染料、発色剤、可塑剤、顔料、難燃剤、安定剤、密着性付与剤を必要に応じて添加してもよい。
【００２８】
本発明の感光性樹脂組成物は、前記各成分を、これらを溶解する溶剤、例えば、トルエン、アセトン、メチルエチルケトン（ＭＥＫ）、メチルイソブチルケトン、メチルセロソルブ、エチルセロソルブ、クロロホルム、塩化メチレン、メチレンアルコール、エチルアルコール等に溶解、混合させることにより、均一な溶液とすることができる。溶液中の溶剤の量は好ましくは１０〜７０重量％である。
【００２９】
本発明の感光性樹脂組成物は、これを支持体上に塗布、乾燥し、感光層を形成し、感光性エレメントとして使用することもできる。支持体としては、重合性フィルム、例えば、ポリエチレンテレフタレート、ポリプロピレン、ポリエチレン等からなるフィルムが用いられ、ポリエチレンテレフタレートフィルムが好ましい。これらの重合体フィルムは、後に感光層から除去可能でなくてはならないため、除去が不可能となるような材質であったり、表面処理が施されものであってはならない。これらの重合体フィルムの厚さは、通常５〜１００μｍ、好ましくは１０〜３０μｍである。これらの重量体フィルムの一つは感光層の支持フィルムとして、他の一つは感光層の保護フィルムとして感光層の両面に積層してもよい。また、感光層の厚さは１０〜１００μｍとすることが好ましい。
【００３０】
本発明の感光性エレメントを用いてフォトレジスト画像を製造するに際しては、前記保護フィルムが存在している場合には、保護フィルムを除去後、感光層を加熱しながら基板に圧着させることにより積層する。積層される表面は、通常、金属面であるが、特に制限はない。感光層の加熱、圧着は通常、９０〜１３０℃、圧着圧力１〜１０ｋｇｆ／ｃｍ²で行われるが、これらの条件には特に制限はない。感光層を前記のように加熱すれば予め基板を予熱処理することは必要でないが、積層性を更に向上させるために基板の予熱処理を行うことができる。
【００３１】
このようにして積層が完了した感光層は、次いで、ネガフィルム又はポジフィルムを用いて活性光により画像的に露光される。この際感光層上存在する重合体フィルムが透明の場合には、そのまま露光してもよく、また、不透明の場合には、当然除去する必要がある。感光性の保護という点からは、重合体フィルムは透明で、この重合体フィルムを残存させたまま、それを通して露光することが好ましい。
【００３２】
活性光は、公知の活性光源、例えば、カーボンアーク、水銀蒸気アーク、キセノンアーク、その他から発生する光が用いられる。感光層に含まれる光重合開始剤の感受性は、通常、紫外線領域において最大であるので、その場合は活性光源は紫外線を有効に放射するものにすべきである。もちろん、光重合開始剤が可視光線に感受するもの、例えば、９，１０−フェナンスレンキノン等である場合には、活性光としては可視光が用いられ、その光源としては前記のもの以外に写真用フラッド電球、太陽ランプなども用いられる。
【００３３】
次いで、露光後、感光層上に重合体フィルムが存在している場合には、これを除去した後、アルカリ水溶液を用いて、例えば、スプレー、揺動浸漬、ブラッシング、スクラッビング等の公知の方法により未露光部を除去して現像する。アルカリ水溶液の塩基としては、リチウム、ナトリウムあるいはカリウムの水酸化物等の水酸化アルカリ、リチウム、ナトリウムあるいはカリウムの炭酸塩又は重炭酸塩等の炭酸アルカリ、リン酸カリウム、リン酸ナトリウム等のアルカリ金属リン酸塩、ピロリン酸ナトリウム、ピロリン酸カリウム等のアルカリ金属ピロリン酸塩などが用いられ、特に、炭酸ナトリウムの水溶液が好ましい。現像に用いるアルカリ水溶液のｐＨは、好ましくは９〜１１の間であり、また、その温度は感光層の現像性に合わせて調節される。該アルカリ水溶液中には、表面活性剤、消泡剤、現像を促進させるための少量の有機溶剤などを混入させてもよい。
【００３４】
更に、印刷配線板を製造するに際しては、現像されたフォトレジスト画像をマスクとして露出している基板の表面をエッチング、めっき等の公知方法で処理する。次いで、フォトレジスト画像は、通常、現像に用いたアルカリ水溶液より更に強アルカリ性の水溶液で剥離される。この強アルカリ性の水溶液としては、例えば、１〜５重量％の水酸化ナトリウム水溶液等が用いられる。
【００３５】
【実施例】
次に、本発明を実施例により詳細に説明するが、本発明はこれらに限定されるものではない。
【００３６】
実施例１〜２及び比較例１〜３
メタクリル酸／メタクリル酸メチル／アクリル酸エチル／メタクリル酸エチル（重合比２２／４５／２７／６（重量比）、重量平均分子量１１万）の４０重量％メチルセロソルブ／トルエン（重量比６／４）溶液１５０ｇ（固形分６０ｇ）（（Ａ）成分）、トリブロモメチルフェニルスルフォン１．０ｇ、ロイコクリスタルバイオレット１ｇ、マラカイトグリーン０．０５ｇ、メチルエチルケトン１０ｇ、トルエン１０ｇ、メタノール３ｇ、ベンゾフェノン４．５ｇ（（Ｂ）成分）及びＮ，Ｎ′−テトラエチル−４，４′−ジアミノベンゾフェノン（（Ｂ）成分）０．２ｇを配合し溶液を得た。
【００３７】
この溶液に表１に示す（Ｃ）成分を溶解させて感光性樹脂組成物の溶液を得た。次いで、この感光性樹脂組成物の溶液を２５μｍ厚のポリエチレンテレフタレートフィルム上に均一に塗布し、１１０℃の熱風対流式乾燥機で約１０分間乾燥して感光性エレメントを得た。感光性樹脂組成物層の乾燥後の膜厚は、５０μｍであった。
【００３８】
一方、銅箔（厚さ３５μｍ）を両面に積層したガラスエポキシ材である銅張り積層板（日立化成工業社製、商品名ＭＣＬ−Ｅ−６１）の銅表面を♯６００相当のブラシを持つ研磨機（三啓社製）を用いて研磨し、水洗後、空気流で乾燥し、得られた銅張り積層板を８０℃に加温し、その銅表面上に前記感光性樹脂組成物層を１２０℃に加熱しながらラミネートした。
【００３９】
次に、高圧水銀灯ランプを有する露光機（オーク（株）製）ＨＭＷ−２０１Ｂを用いてネガとしてストーファー２１段ステップタブレットを試験片の上に置いて６０ｍＪ／ｃｍ²露光した。次にポリエチレンテレフタレートフィルムを剥離し、３０℃で１重量％炭酸ナトリウム水溶液を６０秒間スプレーすることにより、未露光部分を除去した。さらに、銅張り積層板上に形成された光硬化膜のステップタブレットの段数を測定することにより、感光性樹脂組成物の光感度を評価した。その結果を表１に示す。光感度は、ステップタブレットの段数で示され、このステップタブレットの段数が高いほど光感度が高いことを示す。
【００４０】
また、５ｃｍ×５ｃｍの試験片を６０ｍＪ／ｃｍ²で露光後６０秒現像した後５０℃に加温した３重量％ＮａＯＨに浸漬し、レジストが剥離する時間を測定し、剥離片の大きさも同時に測定した。
【００４１】
また、上述の方法で銅張り積層基板にラミネートした積層体に、ポジパターンマスクフィルムを通して超高圧水銀灯により６０ｍＪ／ｃｍ²の紫外線を照射した。次いでポリエチレンテレフタレートフィルムを剥離した後１重量％炭酸ナトリウム水溶液で現像を行い下記条件で前処理、硫酸銅めっき及び半田めっきを行った。得られた画像の細線部分にセロテープを張り、十分圧着した後テープを剥離した。テープ剥離の判定基準を以下に示す。
【００４２】
［前処理条件］
５０℃ ＰＣ−４５５（メルテック社製）２５重量％溶液３分浸漬→水洗→２０重量％過硫酸アンモニウム水溶液１分浸漬→１０重量％硫酸水溶液→水洗
［硫酸銅めっき条件］
メルテックス社製、商品名「硫酸銅コンク」を１９％硫酸で３．６倍に希釈しためっき液中で２．５Α／ｄｍ²の電流密度で室温下３０分めっきを行う。
【００４３】
［半田めっき条件］
マクダーミッド社製の半田めっき液（錫／鉛＝６／４）を用い、２．０Α／ｄｍ²の電流密度で室温下１０分間めっきを行う。
【００４４】
［テープ剥離判定基準］
ａ レジストの剥れが全くない。
【００４５】
ｂ 画像の両側に１００μｍ未満の幅で１ｍｍ未満の長さの部分が処々剥離した。
【００４６】
ｃ 画像の両側に１００μｍ以上の幅で１ｍｍ以上の長さの部分が処々剥離した。
【００４７】
ｄ ほぼ全部のレジストが剥離した。
これらの結果をまとめて表１に示した。
【００４８】
【表１】

＊１： 一般式（Ｉ）でＲ₁＝Ｈ、Α＝−ＣＨ₂ＣＨ₂−、Ｂ＝−ＣＨ（ＣＨ₃）ＣＨ₂−、ｍ₁＋ｍ₂＋ｍ₃＝６、ｎ₁＋ｎ₂＋ｎ₃＝１５の化合物
＊２： 一般式（Ｉ）でＲ₁＝Ｈ、Α＝−ＣＨ₂ＣＨ₂−、Ｂ＝−ＣＨ（ＣＨ₃）ＣＨ₂−、ｍ₁＋ｍ₂＋ｍ₃＝６、ｎ₁＋ｎ₂＋ｎ₃＝３６の化合物
＊３： ビスフェノールΑポリオキシエチレンジメタクリレート（新中村化学工業社製商品名）
＊４： ２，２−ビス［（４−メタクリロキシペンタエトキシ）フェニル］プロパン（サートマ社製商品名）
表１から明らかなように、一般式（Ｉ）で示される化合物を含有させることにより、耐めっき性に優れ、剥離特性も良好な感光性樹脂組成物を得ることができた。
【００４９】
【発明の効果】
本発明の感光性樹脂組成物及びこれを用いた感光性エレメントは、耐めっき性、剥離性に優れたものであり、その工業的価値は極めて大である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a photosensitive resin composition and a photosensitive element using the same.
[0002]
[Prior art]
Conventionally, a so-called dry film resist (hereinafter abbreviated as DFR) composed of a support layer and a photopolymerization layer has been used as a resist for producing a printed circuit board. The DFR is generally prepared by laminating a photopolymerizable layer made of a photopolymerizable composition on a support layer, and in many cases, further laminating a protective film on the photopolymerizable layer.
[0003]
In order to produce a printed circuit board using DFR, the protective film is first peeled off, and then the DFR is laminated on a permanent circuit production substrate such as a copper-clad laminate. Next, if necessary, the support layer is peeled off and exposed through a wiring pattern mask film or the like. When there is a support layer after exposure, the support layer is peeled off if necessary, and a photopolymerization layer in an unexposed portion is dissolved or dispersed and removed by a developer to form a cured resist image on the substrate. As the photopolymerization layer, an alkali developing type using an aqueous alkali solution as a developing solution and a solvent developing type using an organic solvent are known, but in recent years, the demand for an alkali developing type DFR has increased due to environmental problems and costs. .
[0004]
The process for forming the circuit is the same for both types after development, and is roughly divided into two methods. The first method is to further remove the resist after etching away the copper surface not covered with the cured resist, and the second method is to perform plating treatment of copper, solder, etc. on the above copper surface. After that, the resist is removed, and the copper surface that appears is etched.
[0005]
Also, among the printed circuit boards manufactured using DFR, a conductive circuit forming material layer attached to the inner peripheral surface of the through hole, for example, a copper thin film layer is used to connect one surface of the permanent imaging substrate to the other surface. Most of them are electrically connected to the surface. As a method of manufacturing this type of printed circuit board, a copper through-hole method and a solder through-hole method are generally used, and the tenting method has been widely adopted in the copper through-hole method. In the through-hole method, a conductive circuit constituent material on the inner peripheral surface of the through-hole, for example, a copper thin film layer is coated with an etching-resistant metal such as solder plating, and then unnecessary portions of the substrate surface are etched. In various plating processes such as copper plating and solder plating described above, the plating solution penetrates between the resist and the substrate, and if the plating is loosened, a short circuit will occur. Therefore, DFR excellent in plating resistance is required.
[0006]
The cured resist formed by exposure and development is peeled off by a stripping solution of an alkaline aqueous solution such as sodium hydroxide after etching or plating. The peeling speed is preferably fast from the viewpoint of productivity. Moreover, if the solubility of the resist cured film in the stripping solution is high, the viscosity of the stripping solution increases and foaming becomes remarkable. For this reason, the treatment capacity of the stripping solution is reduced. Furthermore, since the BOD (biochemical oxygen demand) and COD (chemical oxygen demand) of the stripping solution increase, the cost required for waste liquid treatment becomes expensive. From the above points, the cured resist film is preferably hardly soluble in the stripping solution.
[0007]
The DFR photopolymerization layer widely used at present is (1) an unsaturated compound having at least one ethylenic group and capable of forming a polymer by a photopolymerization initiator, and (2) a thermoplastic organic polymer bond. (3) a photopolymerization initiator and (4) other additives (Japanese Patent Publication No. 50-9177, Japanese Patent Publication No. 57-21697).
[0008]
As the unsaturated compound, acrylic acid and methacrylic acid esters of aliphatic polyhydric alcohol acids are the most common, and trimethylolpropane triacrylate, pentaerythritol triacrylate, polyethylene glycol diacrylate, and the like are known. In addition, an example is known in which polyethylene glycol or polypropylene glycol is added to bisphenol candy as an aromatic dihydric alcohol and used as acrylic acid or methacrylic acid ester.
[0009]
However, when the former aliphatic ester is used, sufficient plating resistance cannot be obtained. Further, when the latter bisphenol-based monomer is used, it has good plating resistance, but if the side chain is lengthened, the plating resistance is lowered or the compatibility with the binder is impaired. Furthermore, DFR that can be alkali-developed has the characteristics that it has sufficient resistance especially in the plating process as it becomes finer in recent years, and it is quickly peeled off in the peeling process and hardly soluble in the peeling solution. Satisfactory performance is required.
[0010]
[Problems to be solved by the invention]
An object of the present invention is to provide a photosensitive resin composition excellent in plating resistance and releasability, and a photosensitive element using the same.
[0011]
[Means for Solving the Problems]
As a result of intensive studies to solve the above-mentioned problems, the present inventors have developed a compound containing both an ethylene glycol chain and a propylene glycol chain in the molecule of trimethylolpropane acrylic acid and methacrylic acid ester monomers. When it was used as a polymerizable unsaturated compound, it was found that a photosensitive resin composition excellent in plating resistance and peelability was obtained, and the present invention was completed based on this finding.
[0012]
That is, the present invention
(A) a binder polymer having (meth) acrylic acid alkyl ester and (meth) acrylic acid as monomer units ,
(B) a photopolymerization initiator and (C) a photopolymerizable unsaturated compound having at least one polymerizable ethylenically unsaturated bond in the molecule,
In the component (C), an ethylenically unsaturated compound represented by the following general formula (I):

Wherein R ₁ , R ₂ and R ₃ are H or CH ₃ , which may be the same or different. In addition, Α is —CH ₂ CH ₂ —, and B is —CH (CH ₃₎ CH ₂ - or -CH ₂ CH (CH ₃₎ - a Oh _{Ri, m 1, m 2, m} 3, n 1, n 2 and n _{3, m 1 + m 2 + m} 3 is 6-10 N ₁ + n ₂ + n ₃ is a positive integer in the range of 15 to 36. )
Is contained in an amount of 5 to 100 % by weight.
[0013]
[Chemical 2]

(Wherein R ₁ , R ₂ and R ₃ are H or CH ₃ , and these may be the same or different. Α and B are —CH (CH ₃ ) CH ₂ — or — CH ₂ CH (CH ₃ ) — or —CH ₂ CH ₂ —, and Α and B are different from each other, and m ₁ , m ₂ , m ₃ , n ₁ , n _2, and n ₃ are m ₁ + m ₂ + m ₃ is a positive integer in the range of 6 to 45 and n ₁ + n ₂ + n ₃ is in the range of ₃ to 45.)
Is contained in an amount of 5 to 70% by weight.
[0014]
Moreover, this invention relates to the photosensitive element formed by apply | coating said photosensitive resin composition on a support body, and drying.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
In the photosensitive resin composition and photosensitive element of the present invention, when the compound represented by the general formula (I) is used as the photopolymerizable unsaturated compound as the ethylenically unsaturated compound of the component (C), In particular, the resist exhibits sufficient resistance in the plating process, and good releasability in the peeling process, so that the cured film is rich in flexibility.
[0016]
In the photopolymerizable unsaturated compound represented by the formula (I) used in the present invention, when only an ethylene glycol chain is used, if the side chain is lengthened in order to improve the releasability, the hydrophilicity increases and swelling is likely to occur. Sexuality is impaired. Further, when only propylene glycol is used, if the side chain is lengthened in order to improve the releasability, the compatibility with the binder is deteriorated, so that the composition is not uniform and phase separation occurs.
[0017]
Examples of the carboxyl group-containing binder polymer used as the component (A) include (meth) acrylic acid alkyl ester [(meth) acrylic acid means methacrylic acid and acrylic acid. same as below. ], (Meth) acrylic acid, and a copolymer of vinyl monomer copolymerizable with these. These copolymers can be used alone or in combination of two or more.
[0018]
Examples of the (meth) acrylic acid alkyl ester include (meth) acrylic acid methyl ester, (meth) acrylic acid ethyl ester, (meth) acrylic acid butyl ester, (meth) acrylic acid 2-ethylhexyl ester, and the like.
[0019]
Examples of vinyl monomers that can be copolymerized with (meth) acrylic acid alkyl ester and (meth) acrylic acid include (meth) acrylic acid tetrahydrofurfuryl ester, (meth) acrylic acid dimethylaminoethyl ester, (meth) Diethylaminoethyl acrylate, glycidyl methacrylate, 2,2,2-trifluoroethyl (meth) acrylate, 2,2,3,3-tetrafluoropropyl (meth) acrylate, acrylamide, diacetone acrylamide, styrene, vinyl And toluene.
[0020]
Examples of the photopolymerization initiator used as the component (B) of the present invention include benzophenone, N, N′-tetramethyl-4,4′-diaminobenzophenone (Michler ketone), N, N′-tetraethyl-4,4. Aromatic ketones such as' -diaminobenzophenone, 4-methoxy-4'-diaminobenzophenone, 2-ethylanthraquinone, phenanthrenequinone, benzoin ethers such as benzoin methyl ether, benzoin ethyl ether, benzoin phenyl ether, methyl benzoin, ethyl benzoin, etc. Benzyl derivatives such as benzoin, benzyldimethyl ketal, 2- (o-chlorophenyl) -4,5-diphenylimidazole dimer, 2- (o-chlorophenyl) -4,5-di (m-methoxyphenyl) imidazole Mass, -(O-fluorophenyl) -4,5-diphenylimidazole dimer, 2- (o-methoxyphenyl) -4,5-diphenylimidazole dimer, 2,4-di- (p-methoxyphenyl)- 5-phenylimidazole dimer, 2- (2,4-dimethoxyphenyl) -4,5-diphenylimidazole dimer, 2- (p-methylmercaptophenyl) -4,5-diphenylimidazole dimer, etc. Examples include acridine derivatives such as 2,4,5-triarylimidazole dimer, 9-phenylacridine, and 1,7-bis (9,9'-acridinyl) heptane. These can be used alone or in combination of two or more.
[0021]
Among the photopolymerizable compounds having at least one polymerizable ethylenically unsaturated bond used as the component (C) of the present invention, as the ethylenically unsaturated compound represented by the general formula (I) included as an essential component, , M ₁ , m ₂ , m ₃ , n ₁ , n ₂ and n ₃ are positive integers, m ₁ + m ₂ + m ₃ is 6 to 45 (preferably 9 to 24), and n ₁ + n ₂ + n ₃ is There is no particular limitation as long as it is within the range of 3 to 45 (preferably 6 to 24), but the total number of propylene glycol groups contained in the structure is preferably larger than the total number of ethylene glycol groups. More preferably, the total number of glycol groups is 10 or less. In the ethylenically unsaturated compound represented by the general formula (I), if m ₁ + m ₂ + m ₃ is less than 6, the cured film becomes brittle, and if it exceeds 45, the sensitivity, adhesion and strength are inferior, and n ₁ When + n ₂ + n ₃ is less than ₃ , the cured film becomes brittle, and when it exceeds 45, the sensitivity, adhesion and strength are inferior.
[0022]
Examples of the photopolymerizable compound having at least one polymerizable ethylenically unsaturated bond other than the essential component compound used as the component (C) include polyethylene glycol di (meth) acrylate (ethylene group). 2 to 14), trimethylolpropane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylolmethane tri (meth) acrylate, tetramethylolmethanetetra (meth) acrylate, polypropylene glycol di (meth) ) By reacting an α, β-unsaturated carboxylic acid with a polyhydric alcohol such as acrylate (having 2 to 14 propylene groups), dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, etc. Compound obtained Bisphenol Α dioxyethylene di (meth) acrylate, bisphenol Α trioxyethylene di (meth) acrylate, bisphenol Α deoxyoxyethylene di (meth) acrylate, etc. bisphenol Α polyoxyethylene di (meth) acrylate, trimethylolpropane Compounds obtained by adding α, β-unsaturated carboxylic acid to glycidyl group-containing compounds such as triglycidyl ether triacrylate and bisphenol-diglycidyl ether acrylate, polyvalent carboxylic acids such as phthalic anhydride and β-hydroxyethyl ( Esterified product with hydroxyl group and ethylenically unsaturated group such as (meth) acrylate, (meth) acrylic acid methyl ester, (meth) acrylic acid ethyl ester, (meth) acrylic acid butyl ester, (meth) a Alkyl ester of (meth) acrylic acid such as 2-ethylhexyl ester of crylic acid, trimethylolpropane ethoxytriacrylate and the like.
[0023]
In this invention, it is preferable to make the compounding quantity of (A) component into the range of 40-80 weight part with respect to 100 weight part of total amounts of (Α) component and (C) component. More preferably, it is in the range of 45 to 70 parts by weight. If it is less than 40 parts by weight, the photocured product tends to be brittle, and when used as a photosensitive element, the coating property tends to be inferior, and if it exceeds 80 parts by weight, the sensitivity tends to be insufficient.
[0024]
Moreover, it is preferable to make the compounding quantity of (C) component into the range of 20-60 weight part with respect to 100 weight part of total amounts of (A) component and (C) component. More preferably, it is 30 to 55 parts by weight. If the blending amount is less than 20 parts by weight, the sensitivity tends to be insufficient, and if it exceeds 60 parts by weight, the photocured product tends to become brittle.
[0025]
In addition, the compounding quantity of the ethylenically unsaturated compound shown by general formula (I) which is an essential component in (C) component is 5-70 weight% in (C) component, Preferably it is the range of 10-50%. To do. If the blending amount is less than 5% by weight, the peeling time becomes long, and if it exceeds 70% by weight, the tent strength becomes weak.
[0026]
The blending amount of the (B) component photopolymerization initiator is preferably in the range of 0.1 to 20 parts by weight with respect to 100 parts by weight of the total amount of the (A) and (C) components. More preferably, the range is 0.2 to 10 parts by weight. If the amount is less than 0.1 part by weight, the sensitivity tends to be insufficient. If the amount exceeds 20 parts by weight, the absorption on the surface of the composition increases during exposure and the internal photocuring tends to be insufficient. .
[0027]
Dyes, color formers, plasticizers, pigments, flame retardants, stabilizers, and adhesion promoters may be added to the photosensitive resin composition of the present invention as necessary.
[0028]
In the photosensitive resin composition of the present invention, each of the above components is dissolved in a solvent such as toluene, acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone, methyl cellosolve, ethyl cellosolve, chloroform, methylene chloride, methylene alcohol, A uniform solution can be obtained by dissolving and mixing in ethyl alcohol or the like. The amount of solvent in the solution is preferably 10 to 70% by weight.
[0029]
The photosensitive resin composition of the present invention can be applied to a support and dried to form a photosensitive layer and used as a photosensitive element. As the support, a polymerizable film such as a film made of polyethylene terephthalate, polypropylene, polyethylene or the like is used, and a polyethylene terephthalate film is preferable. Since these polymer films must be removable from the photosensitive layer later, they must not be made of a material that cannot be removed or should be subjected to a surface treatment. The thickness of these polymer films is usually 5 to 100 μm, preferably 10 to 30 μm. One of these weight films may be laminated on both sides of the photosensitive layer as a support film for the photosensitive layer and the other as a protective film for the photosensitive layer. The thickness of the photosensitive layer is preferably 10 to 100 μm.
[0030]
When producing a photoresist image using the photosensitive element of the present invention, if the protective film is present, the protective film is removed and then laminated by pressing the photosensitive layer to the substrate while heating. . The surface to be laminated is usually a metal surface, but is not particularly limited. Heating and pressure bonding of the photosensitive layer are usually performed at 90 to 130 ° C. and pressure pressure of 1 to 10 kgf / cm ² , but these conditions are not particularly limited. If the photosensitive layer is heated as described above, it is not necessary to preheat the substrate in advance, but the substrate can be preheated in order to further improve the laminating property.
[0031]
The photosensitive layer thus laminated is then imagewise exposed with actinic light using a negative or positive film. At this time, if the polymer film present on the photosensitive layer is transparent, it may be exposed as it is, and if it is opaque, it must be removed as a matter of course. From the standpoint of protecting the photosensitivity, the polymer film is preferably transparent, and it is preferably exposed through the polymer film while remaining.
[0032]
As the active light, light generated from a known active light source such as a carbon arc, a mercury vapor arc, a xenon arc, or the like is used. The sensitivity of the photopolymerization initiator contained in the photosensitive layer is usually maximum in the ultraviolet region, and in this case, the active light source should emit ultraviolet light effectively. Of course, when the photopolymerization initiator is sensitive to visible light, such as 9,10-phenanthrenequinone, visible light is used as the active light, and the light source other than those described above is used. Photo flood bulbs and solar lamps are also used.
[0033]
Next, after exposure, if a polymer film is present on the photosensitive layer, it is removed and then an aqueous alkaline solution is used, for example, by a known method such as spraying, rocking immersion, brushing, or scrubbing. The unexposed area is removed and developed. Examples of the base of the alkaline aqueous solution include alkali hydroxides such as lithium, sodium or potassium hydroxide, alkali carbonates such as lithium, sodium or potassium carbonate or bicarbonate, alkali metals such as potassium phosphate and sodium phosphate. Alkali metal pyrophosphates such as phosphate, sodium pyrophosphate and potassium pyrophosphate are used, and an aqueous solution of sodium carbonate is particularly preferable. The pH of the aqueous alkaline solution used for development is preferably between 9 and 11, and the temperature is adjusted according to the developability of the photosensitive layer. A surface active agent, an antifoaming agent, a small amount of an organic solvent for promoting development, and the like may be mixed in the alkaline aqueous solution.
[0034]
Furthermore, when manufacturing a printed wiring board, the exposed surface of the substrate is treated by a known method such as etching or plating using the developed photoresist image as a mask. Next, the photoresist image is usually peeled off with a stronger alkaline aqueous solution than the alkaline aqueous solution used for development. As this strongly alkaline aqueous solution, for example, a 1 to 5% by weight sodium hydroxide aqueous solution or the like is used.
[0035]
【Example】
EXAMPLES Next, although an Example demonstrates this invention in detail, this invention is not limited to these.
[0036]
Examples 1-2 and Comparative Examples 1-3
40% by weight methyl cellosolve / toluene (weight ratio 6/4) of methacrylic acid / methyl methacrylate / ethyl acrylate / ethyl methacrylate (polymerization ratio 22/45/27/6 (weight ratio), weight average molecular weight 110,000) 150 g of solution (solid content 60 g) (component (A)), tribromomethylphenylsulfone 1.0 g, leuco crystal violet 1 g, malachite green 0.05 g, methyl ethyl ketone 10 g, toluene 10 g, methanol 3 g, benzophenone 4.5 g ((B ) Component) and N, N'-tetraethyl-4,4'-diaminobenzophenone (component (B)) 0.2 g.
[0037]
The component (C) shown in Table 1 was dissolved in this solution to obtain a photosensitive resin composition solution. Next, this photosensitive resin composition solution was uniformly coated on a 25 μm-thick polyethylene terephthalate film, and dried for about 10 minutes with a hot air convection dryer at 110 ° C. to obtain a photosensitive element. The film thickness after drying of the photosensitive resin composition layer was 50 μm.
[0038]
On the other hand, the copper surface of a copper-clad laminate (trade name MCL-E-61, manufactured by Hitachi Chemical Co., Ltd.), which is a glass epoxy material in which copper foil (thickness 35 μm) is laminated on both sides, is polished with a brush equivalent to # 600. Polishing using a machine (manufactured by Sankeisha Co., Ltd.), washing with water, and drying with an air flow, heating the obtained copper-clad laminate to 80 ° C., and placing the photosensitive resin composition layer on the copper surface Lamination was performed while heating to 120 ° C.
[0039]
Next, an exposure machine (manufactured by Oak Co., Ltd.) HMW-201B having a high-pressure mercury lamp lamp was used as a negative, and a stove 21-step tablet was placed on the test piece and exposed to 60 mJ / cm ² . Next, the polyethylene terephthalate film was peeled off, and a 1% by weight aqueous sodium carbonate solution was sprayed at 30 ° C. for 60 seconds to remove unexposed portions. Furthermore, the photosensitivity of the photosensitive resin composition was evaluated by measuring the number of steps of the step tablet of the photocured film formed on the copper-clad laminate. The results are shown in Table 1. The light sensitivity is indicated by the number of steps of the step tablet, and the higher the number of steps of the step tablet, the higher the light sensitivity.
[0040]
In addition, a 5 cm × 5 cm test piece was exposed at 60 mJ / cm ² and developed for 60 seconds, and then immersed in 3 wt% NaOH heated to 50 ° C., and the time for peeling the resist was measured. It was measured.
[0041]
Further, the laminate laminated on the copper-clad laminate by the above-described method was irradiated with 60 mJ / cm ² of ultraviolet light through a positive pattern mask film with an ultrahigh pressure mercury lamp. Next, the polyethylene terephthalate film was peeled off and developed with a 1% by weight aqueous sodium carbonate solution, followed by pretreatment, copper sulfate plating and solder plating under the following conditions. A cellophane tape was applied to the thin line portion of the obtained image, and the tape was peeled off after sufficient pressure bonding. The criteria for tape peeling are shown below.
[0042]
[Preprocessing conditions]
50 ° C PC-455 (manufactured by Meltec) 3% immersion in 25% by weight solution → water washing → 20% by weight ammonium persulfate aqueous solution immersion for 1 minute → 10% by weight sulfuric acid aqueous solution → water washing [copper sulfate plating conditions]
Plating is performed at room temperature for 30 minutes at a current density of 2.5 kg / dm ² in a plating solution obtained by diluting a trade name “copper sulfate conch” manufactured by Meltex Co., Ltd. with 19% sulfuric acid 3.6 times.
[0043]
[Solder plating conditions]
Using a solder plating solution (Tin / Lead = 6/4) manufactured by McDermid, plating is performed at a current density of 2.0 Α / dm ² for 10 minutes at room temperature.
[0044]
[Tape peeling criteria]
a There is no peeling of the resist.
[0045]
b On both sides of the image, portions with a width of less than 100 μm and a length of less than 1 mm peeled off.
[0046]
c On the both sides of the image, portions with a width of 100 μm or more and a length of 1 mm or more peeled off.
[0047]
d Almost all resist was peeled off.
These results are summarized in Table 1.
[0048]
[Table 1]

* 1: In general formula (I), R ₁ = H, Α = -CH ₂ CH _2- , B = -CH (CH ₃ ) CH _2- , m ₁ + m ₂ + m ₃ = 6, n ₁ + n ₂ + n ₃ = 15 compound * 2: In general formula (I), R ₁ = H, Α = —CH ₂ CH ₂ —, B = —CH (CH ₃ ) CH ₂ —, m ₁ + m ₂ + m ₃ = 6, n ₁ + N ₂ + n ₃ = 36 compounds * 3: Bisphenol-polyoxyethylene dimethacrylate (trade name, manufactured by Shin-Nakamura Chemical Co., Ltd.)
* 4: 2,2-bis [(4-methacryloxypentaethoxy) phenyl] propane (trade name, manufactured by Sartoma)
As is apparent from Table 1, a photosensitive resin composition having excellent plating resistance and good peeling properties could be obtained by containing the compound represented by the general formula (I).
[0049]
【The invention's effect】
The photosensitive resin composition of this invention and the photosensitive element using the same are excellent in plating resistance and peelability, and its industrial value is very large.

Claims (3)

(A) a binder polymer having (meth) acrylic acid alkyl ester and (meth) acrylic acid as monomer units ,
(B) a photopolymerization initiator and (C) a photopolymerizable unsaturated compound having at least one polymerizable ethylenically unsaturated bond in the molecule,
The ethylenically unsaturated compound represented by the following general formula (I) in the component (C)

Wherein R ₁ , R ₂ and R ₃ are H or CH ₃ , which may be the same or different. In addition, Α is —CH ₂ CH ₂ —, and B is —CH (CH ₃₎ CH ₂ - or -CH ₂ CH (CH ₃₎ - a Oh _{Ri, m 1, m 2, m} 3, n 1, n 2 and n _{3, m 1 + m 2 + m} 3 is 6-10 N ₁ + n ₂ + n ₃ is a positive integer in the range of 15 to 36. )
5 to 100 % by weight of a photosensitive resin composition. The use ratio of the components (A), (B) and (C)
(A) 40-80 weight part of a component,
The component (B) is 0.1 to 20 parts by weight and the component (C) is 20 to 60 parts by weight with respect to 100 parts by weight of the total amount of the components (A) and (C). ) The total amount of ingredients is 100 parts by weight.)
The photosensitive resin composition according to claim 1. A photosensitive element obtained by coating the photosensitive resin composition according to claim 1 or 2 on a support and drying.