JP4140264B2 - Photosensitive resin composition, photosensitive element, method for producing resist pattern, and method for producing printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photosensitive resin composition excellent in productivity and also having good resolution and adhesion and a photosensitive element using the same. SOLUTION: The photosensitive resin composition comprises (A) a binder polymer, (B) a photopolymerizable compound having at least one polymerizable, ethylenically unsaturated bond in one molecule, (C) a photopolymerization initiator and (D) a hindered amine compound. The photosensitive element is obtained by forming a resist layer consisting of a layer of the photosensitive resin composition on a support.

Description

（式中、Ｒ_１、Ｒ_２，Ｒ_３，Ｒ_４はそれぞれ独立に、炭素数１〜２０のアルキル基を示す。）
【００３９】
このような（Ｄ）ヒンダードアミン化合物としては、下記式（II）で示される化合物を用いることができる。
【００４０】
【化５】

（式中、Ｒ₅は水素原子またはメチル基、Ｘは酸素原子または−ＮＨ−、Ｙは炭素数０〜１０のアルキレン基または炭素数２〜６のアルキレンオキシ基、Ｒ₁₀は炭素数１〜２０のアルキル基をそれぞれ示す。また、Ｒ₆、Ｒ₇，Ｒ₈，Ｒ₉はそれぞれ独立に炭素数１〜２０のアルキル基を示す。）
上記式（II）中、Ｙの炭素数２〜６のアルキレンオキシ基（−ＲＯ−；ＲはＣ２〜Ｃ６のアルキレン基）は、特に、炭素数２のエチレンオキシ基（−Ｃ₂Ｈ₄Ｏ−）であることが好ましい。
【００４１】
式（II）で示されるヒンダードアミン化合物しては、２，２，６，６，−テトラメチル−４−ピペリジルアクリレ−ト、１，２，２，６，６，−ペンタメチル−４−ピペリジルアクリレ−ト、Ｎ−（２，２，６，６，−テトラメチル−４−ピペリジル）アクリルアミド、Ｎ−（１，２，２，６，６，−ペンタメチル−４−ピペリジル）アクリルアミド、２，２，６，６，−テトラメチル−４−ピペリジルメタクリレ−ト、１，２，２，６，６，−ペンタメチル−４−ピペリジルメタクリレ−ト、Ｎ−（２，２，６，６，−テトラメチル−４−ピペリジル）メタクリルアミド、Ｎ−（１，２，２，６，６，−ペンタメチル−４−ピペリジル）メタクリルアミド、２−（１，２，２，６，６，− ペンタメチル−４−ピペリジルオキシ）エチル（メタ）アクリレ−ト等が挙げられる。
【００４２】
上記例示の化合物のうち、感光性エレメント製造時の感光性樹脂組成物への溶解性という点で、２，２，６，６，−テトラメチル−４−ピペリジルメタクリレ−ト、１，２，２，６，６，−ペンタメチル−４−ピペリジルメタクリレ−ト、２−（１，２，２，６，６，− ペンタメチル−４−ピペリジル）エチルメタクリレ−ト、２−（１，２，２，６，６，− ペンタメチル−４−ピペリジルオキシ）エチルメタクリレ−トが好ましく用いられる。特に好ましくは、２，２，６，６，−テトラメチル−４−ピペリジルメタクリレ−トが、密着性、解像性に優れるので好ましい。
また、上記式（ II ）で示されるヒンダードアミン化合物とともに、式（Ｉ）で示されるピペリジン骨格を有するヒンダードアミン化合物を併用することもでき、これらのヒンダードアミン化合物としては、たとえば、ビス（２，２，６，６，−テトラメチル−４−ピペリジル）セバケート、ビス（１，２，２，６，６，−ペンタメチル−４−ピペリジル）セバケート、１−［２−［３−（３，５−ジ−ｔ−ブチル−４−ヒドロキシフェニル）プロピオニオルオキシ］エチル］−４−［３−（３，５−ジ−ｔ−ブチル−４−ヒドロキシフェニル）プロピオニルオキシ−２，２，６，６，−テトラメチルピペリジン、８−ベンジル−７，７，９，９−テトラメチル−３−オクチル−１，３，８−トリアザスピロ［４，５］ウンデカン−２，４−ジオン、４−ベンゾイルオキシ−２，２，６，６，−テトラメチルピペリジン、こはく酸ジメチル−１−（２−ヒドロキシエチル）−４−ヒドロキシ−２，２，６，６、−テトラメチル−ピペリジン重縮合物などが挙げられる。これらのうち、感光性エレメント製造時の感光性樹脂組成物への溶解性という点で、ビス（２，２，６，６，−テトラメチル−４−ピペリジル）セバケート、が好ましい。
【００４３】
次に、以上の成分（Ａ）〜（Ｄ）の好ましい配合量について説明する。（Ａ）バインダーポリマーの配合量は、（Ａ）成分および（Ｂ）成分の総量１００重量部に対して、光硬化物の硬度（脆さ）と感光性エレメントとして用いた場合の成膜性の観点から４０重量部以上であることが好ましく、光感度の観点から８０重量部以下であることが好ましく、４５〜７０重量部であることがより好ましい。
【００４４】
（Ｂ）光重合性化合物の配合量は、（Ａ）成分および（Ｂ）成分の総量１００重量部に対して、光感度の観点から２０重量部以上であることが好ましく、光硬化物の硬度（脆さ）の観点から６０重量部以下であることが好ましく、３０〜５５重量部であることがより好ましい。
【００４５】
（Ｃ）光重合開始剤の配合量は、（Ａ）成分および（Ｂ）成分の総量１００重量部に対して、光感度の観点から０．１重量部以上であることが好ましく、光硬化性の観点から２０重量部以下であることが好ましく、０．２〜１０重量部であることがより好ましい。この配合量が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充分となる傾向がある。
【００４６】
（Ｄ）成分の配合量は、（Ａ）成分、（Ｂ）成分および（Ｃ）成分の総量１００重量部に対し、感度上昇と経日変化の抑制効果の観点から０．００１重量部以上であることが好ましく、密着性の観点から１０重量部以下であることが好ましく、０．００５〜５重量部であることがより好ましい。
【００４７】
以上の必須の４成分に加え、本発明の感光性樹脂組成物には、必要に応じて、マラカイトグリーン等の染料、トリブロモフェニルスルホン、ロイコクリスタルバイオレット等の光発色剤、熱発色防止剤、ｐ−トルエンスルホンアミド等の可塑剤、顔料、充填剤、消泡剤、難燃剤、上記（Ｄ）ヒンダードアミン化合物以外の安定剤、密着性付与剤、レベリング剤、剥離促進剤、酸化防止剤、香料、イメージング剤、熱架橋剤などを、（Ａ）成分および（Ｂ）成分の総量１００重量部に対して各々０．０１〜２０重量部程度含有することができる。これらは単独で、または２種類以上を組み合わせて用いることができる。
【００４８】
本発明の感光性樹脂組成物は、必要に応じて、メタノール、エタノール、アセトン、メチルエチルケトン、メチルセロソルブ、エチルセロソルブ、トルエン、Ｎ，Ｎ−ジメチルホルムアミド、プロピレングリコールモノメチルエーテル等の溶剤またはこれらの混合溶剤に溶解して、固形分３０〜６０重量％程度の溶液として塗布することができる。その用途は、特に制限はないが、金属面、たとえば、銅、銅系合金、ニッケル、クロム、鉄、ステンレス等の鉄系合金、好ましくは銅、銅系合金、鉄系合金の表面上に液状レジストとして塗布して乾燥後、必要に応じて保護フィルムを被覆して用いるか、または、感光性エレメントの形態で用いられることが好ましい。
【００４９】
塗布される感光性樹脂組成物層の厚みは、用途により異なるが、乾燥後の厚みで、工業的な塗工の容易性という観点から１μｍ以上であることが好ましく、接着力、解像度の観点から１００μｍ以下であることが好ましく、１〜５０μｍ程度であることがより好ましい。また、得られる感光性樹脂組成物層は、波長３６５ｎｍの紫外線に対する透過率が、密着性の観点から５％以上であることが好ましく、解像度の観点から７５％以下であることが好ましく、７〜６０％であることがより好ましく、１０〜４０％であることが特に好ましい。上記透過率は、ＵＶ分光計により測定することができ、ＵＶ分光計としては、（株）日立製作所製２２８Ａ型Ｗビーム分光光度計等が挙げられる。
【００５０】
次に、本発明に係る感光性エレメント、すなわち、上述した本発明に係る感光性樹脂組成物からなるレジスト層が支持体上に形成されてなる感光性エレメントについて、図面を参照しながら説明する。
【００５１】
図１は、感光性エレメントの一実施形態を模式的に示したものであり、感光性エレメント１は、支持体１１と、その上に形成されたレジスト層（感光性樹脂組成物層）１２とを含んでいる。
【００５２】
支持体１１としては、たとえば、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、ポリエステル等の耐熱性および耐溶剤性を有する重合体フィルムを好ましく用いることができる。支持体の厚みは、現像前の剥離時の強度の観点から５μｍ以上であることが好ましく、解像度の観点から２５μｍ以下であることが好ましく、８〜２０μｍであることがより好ましく、１０〜１６μｍであることが特に好ましい。また、支持体１１のヘーズは、０．００１％以上であることが好ましく、解像度の観点から５．０％以下であることが好ましく、０．００１〜２．０％であることがより好ましく、０．０１〜１．８％であることが特に好ましい。上記ヘーズは、ＪＩＳ Ｋ ７１０５に準拠して測定され、たとえば、ＮＤＨ−１００１ＤＰ（日本電色工業（株）製、商品名）等の市販の濁度計などで測定が可能である。
【００５３】
支持体１１上へのレジスト層１２の形成方法は、特に限定されないが、感光性樹脂組成物の溶液を塗布、乾燥することにより好ましく得ることができる。塗布されるレジスト層の厚みは、用途により異なるが、上述のように、乾燥後の厚みで１〜１００μｍ程度であることが好ましく、１〜５０μｍ程度であることがより好ましい。塗布は、たとえば、ロールコータ、コンマコータ、グラビアコータ、エアーナイフコータ、ダイコータ、バーコータ等の公知の方法で行うことができる。乾燥は、５０〜２００℃、０．５〜２０分間程度で、好ましくは８０〜１６０℃、１〜１０分間程度で行うことができる。また、レジスト層１２中の残存有機溶剤量は、後の工程での有機溶剤の拡散を防止する点から、２重量％以下とすることが好ましい。
【００５４】
感光性エレメント１のレジスト層表面は、ポリエチレン、ポリプロピレン等の重合体フィルムからなる保護フィルム（図示せず）で被覆することが好ましい。保護フィルムの厚みは、ラミネートの際の強度の観点から５μｍ以上であることが好ましく、廉価性の観点から３０μｍであることが好ましく、１０〜２８μｍであることがより好ましく、１５〜２５であることが特に好ましい。
【００５５】
保護フィルムのフィルム長手方向の引張強さは、ラミネートの際の強度の観点から１３ＭＰａ以上であることが好ましく、１３〜１００ＭＰａであることがより好ましく、１４〜１００ＭＰａであることがさらに好ましく、１５〜１００ＭＰａであることが非常に好ましく、１６〜１００ＭＰａであることが極めて好ましい。また、その幅方向の引張強さは、ラミネートの際の強度の観点から９ＭＰａ以上であることが好ましく、９〜１００ＭＰａであることがより好ましく、１０〜１００ＭＰａであることがさらに好ましく、１１〜１００ＭＰａであることが非常に好ましく、１２〜１００ＭＰａであることが極めて好ましい。ここで、引張強さは、ＪＩＳ Ｃ ２３１８−１９９７（５．３．３）に準拠して測定することができ、たとえば、東洋ボールドウィン（株）製商品名テンシロン等の市販の引張強さ試験機などで測定が可能である。
【００５６】
これら支持体および保護フィルムは、後にレジスト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表面処理が施されたものであってはならないが、必要に応じて表面処理が施されていてもよい。たとえば、これらの支持体、保護フィルムは、必要に応じて帯電防止処理が施されていてもよい。また、レジスト層と支持体との接着力よりも、レジスト層と保護フィルムとの接着力のほうが小さいものを選択することが好ましい。
【００５７】
支持体とレジスト層と、必要に応じて保護フィルムとからなる２層または３層構造の感光性エレメントは、さらに、図には示されていないが、クッション層、接着層、光吸収層、ガスバリア層等の中間層や保護層を有していてもよい。
【００５８】
このようにして得られる感光性エレメントは、たとえば、そのまま、またはレジスト層の表面にさらに保護フィルムを積層して、円筒状の巻芯にロール状に巻きとって貯蔵される。
【００５９】
また、別の本発明の感光性エレメントは、支持体と、前記支持体上に塗布され８０℃以上で乾燥されてなるレジスト層とを含むものである。
【００６０】
支持体としては、上述の感光性エレメントで説明したと同様のものを好ましく用いることができる。レジスト層としては、８０℃以上という乾燥温度に耐えうるものであって、乾燥工程の熱による感度上昇や経日変化等の問題が生じないものであれば、特に限定されることはない。一例として、上記本発明の感光性樹脂組成物を好ましく用いることができる。
【００６１】
レジスト層の塗布は、たとえば、ロールコータ、コンマコータ、グラビアコータ、エアーナイフコータ、ダイコータ、バーコータ等の公知の方法で行うことができる。塗布されるレジスト層の厚みは、用途により異なるが、乾燥後の厚みで１〜１００μｍ程度であることが好ましく、１〜５０μｍ程度であることがより好ましい。
【００６２】
塗布されたレジスト層の乾燥は、８０℃以上で行われ、好ましくは８０〜２００℃で０．５〜２０分間程度、さらに好ましくは８０〜１６０℃で１〜１０分間程度行うことができる。また、レジスト層中の残存有機溶剤量は、後の工程での有機溶剤の拡散を防止する点から、２重量％以下とすることが好ましい。
【００６３】
形成されたレジスト層表面は、保護フィルムで被覆することが好ましく、保護フィルムとしては、上述の感光性エレメントで説明したと同様のものを好ましく用いることができる。その他の感光性エレメントの構成等については、上述の感光性エレメントについて記載したと同様である。
【００６４】
次に、本発明に係るレジストパターンの製造法について、その工程の一例を模式的に示した図２を参照しながら説明する。
【００６５】
まず、工程（ｉ）として、上述した本発明の感光性樹脂組成物からなるレジスト層を基板（回路形成用基板）２上に積層する。積層方法は任意であるが、たとえば、図２（Ａ）にみるように、基板２上に、上述した感光性エレメント１を、レジスト層１２が基板２の表面に密着するようにして積層する。積層に先立ち、感光性エレメント１のレジスト層１２上に保護フィルム（図示せず）が存在している場合には、保護フィルムを除去する。この積層方法としては、たとえば、レジスト層１２を７０〜１３０℃程度に加熱しながら、基板２に０．１〜１ＭＰａ程度（１〜１０ｋｇｆ／ｃｍ²程度）の圧力で圧着することにより積層する方法が挙げられる。密着性および追従性の観点から、減圧下で積層することが好ましい。なお、基板としては、たとえば、ガラス繊維入りエポキシ樹脂等からなるベース上に銅等の金属からなる被加工層を有するものが用いられ、積層される基板２の表面は通常金属面であるが、特に制限はない。また、レジスト層を前記のように７０〜１３０℃に加熱すれば、予め基板を予熱処理することは必要ではないが、積層性をさらに向上させるために、基板の予熱処理を行うこともできる。
【００６６】
レジスト層の積層が完了した後、工程（ii）として、画像状に活性光線を照射して、露光部の前記レジスト層を光硬化させる。画像状に活性光線を照射させる方法として、たとえば、図２（Ｂ）にみるように、アートワークと呼ばれるネガ型またはポジ型マスクパターン３を通してレジスト層１２上に画像状に活性光線を照射し、露光部のレジスト層１２を光硬化させることができる。活性光線の光源としては、公知の光源、たとえば、カーボンアーク灯、水銀蒸気アーク灯、超高圧水銀灯、高圧水銀灯、キセノンランプ等の紫外線を有効に放射するものが用いられる。また、写真用フラッド電球、太陽ランプ等の可視光を有効に放射するものも用いられる。また、マスクパターンを用いずにレーザー直接描画露光を行うこともできる。なお、工程（ii）の露光は、レジスト層１２への光照射が妨げられない限り（支持体が透明である場合等）、支持体１１が存在した状態で行うことができる。
【００６７】
露光後、感光性樹脂組成物層上に支持体が存在している場合には、支持体を除去した後、工程（iii）として、未露光部のレジスト層を現像により選択的に除去することにより、図２（Ｃ）に示すようにレジストパターン１２１が形成される。現像は、ウエット現像、ドライ現像等で行われ、ウエット現像の場合は、アルカリ性水溶液、水系現像液、有機溶剤等のレジスト層の組成に対応した現像液にを用いて、ディップ方式、揺動浸漬方式、バトル方式、スプレー方式、ブラッシング、スラッピング等の公知の方法により行われる。なかでも、高圧スプレー方式が解像度向上のためには最も適している。また、必要に応じて２種以上の現像方法を併用してもよい。
【００６８】
現像液としては、アルカリ性水溶液等の安全かつ安定であり、操作性が良好なものが用いられる。上記アルカリ性水溶液の塩基としては、たとえば、リチウム、ナトリウムまた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、カリウムまたはアンモニウムの炭酸塩もしく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る。なかでも、たとえば、０．１〜５重量％炭酸ナトリウムの希薄溶液、０．１〜５重量％炭酸カリウムの希薄溶液、０．１〜５重量％水酸化ナトリウムの希薄溶液、０．１〜５重量％四ホウ酸ナトリウムの希薄溶液等が好ましい。このアルカリ性水溶液のｐＨは９〜１１の範囲とすることが好ましく、その温度は、感光性樹脂組成物層の現像性に合わせて調節される。また、アルカリ性水溶液中には、界面活性剤、消泡剤、現像を促進させるための少量の有機溶剤等を混入させてもよい。
【００６９】
上記水系現像液としては、水またはアルカリ水溶液と一種以上の有機溶剤とからなる。ここでアルカリ物質としては、上記物質以外に、たとえば、ホウ砂やメタケイ酸ナトリウム、水酸化テトラメチルアンモニウム、エタノールアミン、エチレンジアミン、ジエチレントリアミン、２ーアミノ−２−ヒドロキシメチル−１、３−プロパンジオール、１、３−ジアミノプロパノール−２、モルホリン等が挙げられる。現像液のｐＨは、レジストの現像が充分にできる範囲で、できるだけ小さくすることが好ましく、ｐＨ８〜１２とすることが好ましく、ｐＨ９〜１０とすることがより好ましい。上記有機溶剤としては、たとえば、三アセトンアルコール、アセトン、酢酸エチル、炭素数１〜４のアルコキシ基をもつアルコキシエタノール、エチルアルコール、イソプロピルアルコール、ブチルアルコール、ジエチレングリコールモノメチルエーテル、ジエチレングリコールモノエチルエーテル、ジエチレングリコールモノブチルエーテル等が挙げられる。これらは単独で、または２種類以上を組み合わせて使用される。有機溶剤の濃度は、通常、２〜９０重量％とすることが好ましく、その温度は、現像性にあわせて調整することができる。また、水系現像液中には、界面活性剤、消泡剤等を少量混入することもできる。
【００７０】
単独で用いられる有機溶剤系現像液としては、たとえば、１，１，１−トリクロロエタン、Ｎ−メチルピロリドン、Ｎ，Ｎ−ジメチルホルムアミド、シクロヘキサノン、メチルイソブチルケトン、γ−ブチロラクトン等が挙げられる。これらの有機溶剤は、引火防止のため、１〜２０重量％の範囲で水を添加することが好ましい。
【００７１】
現像後の処理として、必要に応じて６０〜２５０℃程度の加熱又は０．２〜１０Ｊ／ｃｍ²程度の露光を行うことにより、形成されたレジストパターンをさらに硬化するようにしてもよい。
【００７２】
次に、本発明に係るプリント配線板の製造法について、その工程の一例を模式的に示した図３および図４を参照しながら説明する。
【００７３】
レジストパターンを形成するまでの工程は、（ｉ）積層工程、（ｉｉ）露光工程、および（ｉｉｉ）現像工程を含む上述のレジストパターン製造法において説明したものと同様である。その後の回路形成工程（ｉｖ）に関し、図３にはエッチングを用いたサブストラクティブ法を示し、図４にはめっきを用いたセミアディティブ法を示す。
【００７４】
レジストパターン１２１が形成された後、工程（ｉｖ）として、図３（Ｂ）にみるように、形成されたレジストパターン１２１をマスクとして、表面に被加工層２１を有する基板（回路形成用基板）２の被加工層２１をエッチングするか、または、図４（Ｂ）にみるように、被加工層２１上に選択的にめっきを施して、銅等からなるめっき層２２を形成する。図３（Ｂ）における金属面からなる被加工層２１のエッチングには、たとえば、塩化第二銅溶液、塩化第二鉄溶液、アルカリエッチング溶液、過酸化水素系エッチング液を用いることができるが、エッチファクタが良好な点から塩化第二鉄溶液を用いることが望ましい。また、図４（Ｂ）におけるめっき法としては、たとえば、硫酸銅めっき、ピロリン酸銅めっき等の銅めっき、ハイスローはんだめっき等のはんだめっき、ワット浴（硫酸ニッケル−塩化ニッケル）めっき、スルファミン酸ニッケルめっき等のニッケルめっき、ハード金めっき、ソフト金めっき等の金めっきなどがある。
【００７５】
最後に、図３（Ｃ）および図４（Ｃ）にみるように、基板２上に残っているレジストパターン１２１を、たとえば、現像に用いたアルカリ性水溶液よりさらに強アルカリ性の水溶液で剥離して、回路２１１が形成されたプリント配線板４を得ることができる。また、セミアディティブ法の場合は、図４（Ｄ）に示すように、レジストパターン１２１を剥離した後、たとえばクイックエッチング法等により、その下の被加工層２１も除去される。上記強アルカリ性の水溶液としては、たとえば、１〜１０重量％水酸化ナトリウム水溶液、１〜１０重量％水酸化カリウム水溶液等が用いられる。剥離方式としては、たとえば、浸漬方式、スプレイ方式等が挙げられ、浸漬方式およびスプレイ方式を単独で使用してもよいし、併用してもよい。また、レジストパターンが形成されたプリント配線板は、多層プリント配線板でもよい。
【００７６】
【実施例】
以下に、実施例により本発明をさらに詳しく説明するが、本発明の技術思想を逸脱しない限り、本発明はこれらの実施例に限定されるものではない。
［実施例１〜４、参考例５および比較例１〜３］
表１に示す材料を配合し、感光性樹脂組成物の溶液＃１〜＃５を得た。
【００７７】
【表１】

＊１：２，２−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、新中村化学工業（株）製
＊２：ＥＯ変性ノニルフェニルアクリレート（エチレングリコール鎖の繰り返し単位は８）、共栄社化学（株）製
＊３：ポリプロピレングリコールジアクリレート（プロピレングリコール鎖の繰り返し単位は６〜７）、新中村化学工業（株）製
＊４：２，２，６，６，−テトラメチル−４−ピペリジルメタクリレ−ト、日立化成工業（株）製
＊５：ビス（２，２，６，６，−テトラメチル−４−ピペリジル）セバケート、三共（株）製
＊６：ハイドロキノンモノメチルエーテル、精工化学（株）製
【００７８】
次いで、得られた感光性樹脂組成物の溶液を、１６μｍ厚のポリエチレンテレフタレートフィルム（ヘーズ：１．７％、商品名ＧＳ−１６，帝人（株）製）上に均一に塗布し、熱風対流式乾燥機を用いて表２に示す所定の条件で乾燥した。その後、得られた感光性樹脂組成物層（レジスト層）の表面をポリエチレン製保護フィルム（フィルム長手方向の引張強さ：１６ＭＰａ、フィルム幅方向の引張強さ：１２ＭＰａ、商品名：ＮＦ−１５，タマポリ（株）製）で保護し、実施例１〜４、参考例５および比較例１〜３の感光性エレメントを得た。レジスト層の乾燥後の膜厚は、いずれも５０μｍであった。
【００７９】
【表２】

【００８０】
作製後２３℃±２℃ ＲＨ６０％の室内において遮光状態で４時間および３０日間経過後の各感光性エレメントについて、以下の諸特性を各々測定した。諸特性の評価にあたり、銅箔（厚み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（株）製、商品名ＭＣＬ−Ｅ−６１）を８０℃に加温し、その銅表面上に得られた感光性エレメントを、レジスト層上の保護フィルムを剥がしながら、１２０℃のヒートロールを用い、３ｍ／分の速度でラミネートした。なお、感光性エレメントの積層に先立ち、銅張り積層板の銅表面を＃６００相当のブラシを持つ研磨機（三啓（株）製）を用いて研磨し、水洗後、空気流で乾燥させた。
【００８１】
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で露光した。
【００８２】
＜感度＞
試験片のポリエチレンテレフタレートフィルムを剥離し、３０℃の１重量％炭酸ナトリウム水溶液を６０秒間スプレーし、未露光部分を除去した後、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。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。
【００８３】
＜解像度＞
ストーファーの２１段ステップタブレットを有するフォトツールと解像度評価用ネガとしてライン幅／スペース幅が３０／３０〜２００／２００（単位：μｍ）の配線パターンを有するフォトツールとを密着させ、ストーファーの２１段ステップタブレットの現像後の残存ステップ段数が８．０となるエネルギー量で露光を行った。現像処理によって未露光部をきれいに除去することができたライン幅間のスペース幅の最も小さい値により、解像度を評価した。解像度は、数値が小さいほど良好である。
【００８４】
＜耐めっき性＞
上記のように、銅張り積層板にラミネートされ、所定の露光量により露光を行い、次いで、上記現像液により現像した試験片に対し、以下の前処理を行った。まず、脱脂浴（ＰＣ−４５５（メルテックス社製）２５重量％）に５分間浸漬し、水洗し、続いて、ソフトエッチング浴（過硫酸アンモニウム１５０ｇ／リットル）に２分間浸漬し、水洗し、さらに、１０重量％硫酸浴に１分間浸漬した。得られた試験片を、硫酸銅めっき浴（硫酸銅７５ｇ／リットル、硫酸１９０ｇ／リットル、塩素イオン５０ｐｐｍ、カパーグリームＰＣＭ（メルテックス社製）５ミリリットル／リットル）に入れ、硫酸銅めっきを室温下、３Ａ／ｄｍ²で４０分間行った。
【００８５】
その後、試験片を水洗して、１０重量％ホウフッ化水素酸に１分浸漬し、ハンダめっき浴（４５重量％ホウフッ化スズ６４ミリリットル／リットル、４５重量％ホウフッ化鉛２２ミリリットル／リットル、４２重量％ホウフッ化水素酸２００ミリリットル／リットル、プルティンＬＡコンダクティビティーソルト（メルテックス社製）２０ｇ／リットル、プルティンＬＡスターター（メルテックス社製）４１ミリリットル／リットル）に入れ、半田めっきを室温下、１．５Ａ／ｄｍ²で１５分間行った。
【００８６】
試験片を水洗、乾燥後、試験片の耐めっき性を調べるため直ちに９０°ピールオーフ試験を行った。９０°ピールオーフ試験とは、めっき処理が施された基板にセロハンテープを貼り、ゴムローラでよく密着させ、これをピール角度９０℃で瞬時に引き剥がし、セロハンテープへのレジスト転写度合いを観察することである。また、９０°ピールオーフ試験後、レジストを剥離し、上方から光学顕微鏡、投影機等を用いて、半田めっきのもぐりの有無を観察した。半田めっきのもぐりが生じた場合、透明なレジストを介して、その下部に半田めっきにより析出した半田が観察される。
【００８７】
＜密着性＞
別の試験片を、ストーファー２１段ステップタブレットで８段を示す露光量で、露光、現像後、クロスカット試験（ＪＩＳ−Ｋ−５４００）を行った。クロスカット試験とは、感光性エレメントが積層された回路形成用基板の中央に、カッターガイドを用いて、直交する縦横１１本ずつの平行線を１ｍｍの間隔で引き、１ｃｍ²の中に１００個の正方形ができるように碁盤目状の切り傷をつけ、傷の状態を評価することにより行われる。切り傷は、カッターナイフの刃先を感光性エレメントに対して３５〜４５度の範囲の一定の角度に保ち、レジスト層を貫通して回路形成用基板に届くように、切り傷１本について０．５秒かけて等速に引いた。傷の状態の評価は以下の通りである。
【００８８】
１０点：切り傷の１本ごとが細く、両面が滑らかであり、切り傷の交点と正方形の一目一目にはがれがない。
８点：切り傷の交点にわずかなはがれがあるが、正方形の一目一目にははがれがなく、欠損部の面積が全正方形面積の５％以内である。
６点：切り傷の両側と交点とにはがれがあり、欠損部の面積が全正方形面積の５〜１５％である。
４点：切り傷によるはがれの幅が広く、欠損部の面積が全正方形面積の１５〜３５％である。
２点：切り傷によるはがれの幅が４点よりも広く、欠損部の面積が全正方形面積の３５〜６５％である。
０点：欠損部の面積が全正方形面積の６５％以上である。
以上得られた結果を、表３および表４に示す。
【００８９】
【表３】

【００９０】
【表４】

【００９１】
表３および表４から明らかであるように、実施例１〜４では、感光性エレメント作製時の乾燥温度が高くても感度上昇が抑えられ、３０日経過時の変化も見られなかった。また、実施例のレジスト層の解像度、クロスカット性（密着性）および耐めっき性は、いずれも良好であった。
【００９２】
［参考例１］
メタノール３．０ｇと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３．０ｇの混合溶液にトルエン６．０ｇを配合し、溶液を得た。
【００９３】
［参考例２］
メタノール６．０ｇ、トルエン６．０ｇおよび２，４，５−トリアリールイミダゾール二量体３．０ｇを混合し、溶液を得た。
【００９４】
［参考例３］
アセトン１０．０ｇ、ジメチルホルムアミド３．０ｇ、トルエン７．０ｇおよび２，４，５−トリアリールイミダゾール二量体３．０ｇを混合し、溶液を得た。
【００９５】
参考例１および２で得られた溶液における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の溶解性は、参考例３で得られた溶液における溶解性よりも優れていた。また、参考例１および２で得られた溶液を光重合開始剤として配合した感光性樹脂組成物は、参考例３で得られた溶液を光重合開始剤として配合した感光性樹脂組成物よりも、光感度のバラツキを抑える傾向があった。
【００９６】
【発明の効果】
本発明の感光性樹脂組成物は、感光性エレメントを製造する際の高温乾燥が可能であるため乾燥時間の短縮化を図ることができるとともに感度が安定化するので高生産性を実現できるほか、解像度、密着性、耐薬品性（耐めっき性）にも優れているため、プリント配線用回路形成レジストとして、特に有用である。
【図面の簡単な説明】
【図１】図１は、本発明に係る感光性エレメントの一実施形態を示す模式図である。
【図２】図２は、本発明に係るレジストパターンの製造法の一工程例を示す模式図である。
【図３】図３は、本発明に係るプリント配線板の製造法の一工程例を示す模式図である。
【図４】図４は、本発明に係るプリント配線板の製造法の一工程例を示す模式図である。
【符号の説明】
１ 感光性エレメント
１１ 支持体
１２ レジスト層（感光性樹脂組成物層）
２ 基板（回路形成用基板）
１２１ レジストパターン
２１ 被加工層
２１１ 回路
４ プリント配線板[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a photosensitive resin composition, a photosensitive element, a method for producing a resist pattern, and a method for producing a printed wiring board.
[0002]
[Prior art]
In recent years, photosensitive resins that are cured by light such as infrared, visible, ultraviolet, and electron beams can be improved in work environment and can be highly productive. Examples of the application include woodwork / can coatings, adhesives, ink, plate making, circuit forming resists, and the like. This photosensitive resin is classified according to its polymerization form, such as radical polymerization type, ionic polymerization type, and ring-opening polymerization type. In the case of a radical polymerization type photosensitive resin, a photopolymerization initiator that generates radicals by light irradiation is used.
[0003]
However, since the polymerizable monomer contained in the photopolymerization initiator or the resin composition is poor in stability, it is common to use a polymerization inhibitor that controls radical polymerization. For example, in the case of a resist for circuit formation, specific stabilizers having both curability, that is, sensitivity and storage stability are known (Japanese Patent Laid-Open Nos. 11-65104 and 11-60965). . In addition, the resist for circuit formation is generally cured by irradiating a photosensitive resin with ultraviolet light, and as a photopolymerization initiator in this case, a benzophenone-based compound has conventionally been used frequently. Under the demand for high productivity and energy saving, photopolymerization initiators based on 2,4,5-imidazole dimer system that can be cured with a lower exposure energy amount are rapidly spreading.
[0004]
In general, a photosensitive element obtained by using a support and, if necessary, a protective film on a photosensitive resin is widely used for resist formation. The photosensitive element is manufactured by applying a photosensitive resin on a support so as to have a predetermined thickness, drying, and then attaching a protective film to the surface of the photosensitive resin layer as necessary. The drying step is usually performed at 50 to 200 ° C.
[0005]
[Problems to be solved by the invention]
However, the 2,4,5-imidazole dimer has been reported to dissociate due to heat (Macromolecueles No. 28, p636, 1995), and in fact, the photosensitive element using this photopolymerization initiator was used. In manufacturing, due to the influence of heat in the drying process, in addition to the temporary increase in sensitivity immediately after manufacturing, there may also be a “daily change” in which the sensitivity gradually decreases thereafter, which is a problem. . Therefore, the drying temperature must be kept low to about 80 ° C. or less, and there is a problem that the drying time becomes long and productivity is lowered. In addition, in order to suppress the increase in sensitivity, the addition of polymerization inhibitors generally used in radical polymerization systems reduces the curability when forming a resist for circuit formation, and the productivity of printed circuit boards. In addition, there is a problem that various resist properties such as resolution and adhesion are also reduced.
[0006]
Therefore, an object of the present invention is to provide a photosensitive resin composition that can shorten the drying time, is excellent in productivity, and has various resist properties such as resolution and adhesion.
[0007]
Another object of the present invention is to provide a photosensitive element which is excellent in productivity and also has good resolution and adhesion.
[0008]
Another object of the present invention is to provide a method for producing a resist pattern excellent in productivity, adhesion, resolution and the like.
[0009]
Still another object of the present invention is to provide a method for producing a printed wiring board excellent in productivity, adhesion, resolution and the like.
[0010]
[Means for Solving the Problems]
According to a first aspect of the present invention, (A) a binder polymer, (B) a photopolymerizable compound having at least one polymerizable ethylenically unsaturated bond in the molecule, (C) a photopolymerization initiator, and (D) A photosensitive resin composition containing a hindered amine compound is provided.
[0011]
According to a second aspect of the present invention, there is provided a photosensitive element comprising a support and a resist layer comprising the photosensitive resin composition according to the present invention formed on the support, that is, the book. There is provided a photosensitive element in which a resist layer comprising the photosensitive resin composition according to the invention is formed on a support.
[0012]
Furthermore, according to the 3rd side surface of this invention, the photosensitive element containing a support body and the resist layer apply | coated on the said support body and dried at 80 degreeC or more is provided.
[0013]
According to the fourth aspect of the present invention, there is provided a method for producing a resist pattern including the following steps: (i) a step of laminating a resist layer comprising the photosensitive resin composition according to the present invention on a substrate. (Ii) irradiating actinic rays in an image shape to photocur the resist layer in the exposed portion; (iii) selectively removing the resist layer in the unexposed portion by development to form a resist pattern; Process.
[0014]
According to the fifth aspect of the present invention, there is provided a method for producing a printed wiring board including the following steps: (i) A resist layer comprising the photosensitive resin composition according to the present invention is processed on the surface. A step of laminating the substrate having a layer on the layer to be processed; (ii) a step of irradiating the image with an actinic ray to photocur the resist layer in an exposed portion; (iii) the resist layer in an unexposed portion (Iv) etching the layer to be processed of the substrate using the resist pattern as a mask or selectively plating the layer to be processed of the substrate. Process.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail. In the present invention, (meth) acrylic acid means acrylic acid and methacrylic acid corresponding thereto, (meth) acrylate means acrylate and corresponding methacrylate, (meth) acryloyl group means acryloyl group and The corresponding methacryloyl group is meant.
[0016]
The photosensitive resin composition of the present invention comprises (A) a binder polymer, (B) a photopolymerizable compound having at least one polymerizable ethylenically unsaturated bond in the molecule, (C) a photopolymerization initiator system, and (D) Contains a hindered amine compound. In the photosensitive resin composition of the present invention, the photopolymerization initiator of (C) is thermally stabilized by the hindered amine compound (polyalkyl-substituted piperidine derivative) of (D), which is a stabilizer. The drying temperature can be selected without worrying about the influence, the drying time can be shortened, and the sensitivity can be stabilized, so that productivity can be increased. Further, since it is not necessary to add a polymerization inhibitor that leads to a decrease in resolution and adhesion, it is possible to ensure good resolution, adhesion, plating resistance and other characteristics.
[0017]
The (A) binder polymer preferably has a dispersity (weight average molecular weight / number average molecular weight) of 1.0 or more, and preferably 3.0 or less from the viewpoint of adhesiveness and resolution. More preferably, it is -2.0. Here, the weight average molecular weight and the number average molecular weight in the present invention are values measured by gel permeation chromatography and converted to standard polystyrene. Further, the weight average molecular weight is preferably 5,000 or more from the viewpoint of developer resistance, and preferably 300,000 or less from the viewpoint of the length of development time, and 10,000 to 150,000. It is more preferable that Further, the acid value is preferably 100 mgKOH / g or more from the viewpoint of the length of development time, preferably 500 mgKOH / g or less from the viewpoint of the developer resistance of the photocured resist, and 100 to 300 mgKOH / G is more preferable.
[0018]
Specifically, (A) the binder polymer is not particularly limited, and is a polyester resin, an acrylic resin, a styrene resin, an epoxy resin, an amide resin, an amide epoxy resin, an alkyd resin, a phenol resin, A urethane resin etc. can be illustrated. From the standpoint of alkali developability, it is preferable to use an acrylic resin. These can be used alone or in combination of two or more.
[0019]
Moreover, this (A) binder polymer can be manufactured by radically polymerizing a polymerizable monomer. Examples of the polymerizable monomer include polymerizable styrene derivatives substituted at the α-position or aromatic ring such as styrene, vinyltoluene and α-methylstyrene, acrylamide such as diacetone acrylamide, acrylonitrile, vinyl- Esters of vinyl alcohol such as n-butyl ether, (meth) acrylic acid alkyl ester, (meth) acrylic acid tetrahydrofurfuryl ester, (meth) acrylic acid dimethylaminoethyl ester, (meth) acrylic acid diethylaminoethyl ester, (meta ) Acrylic acid glycidyl ester, 2,2,2-trifluoroethyl (meth) acrylate, 2,2,3,3-tetrafluoropropyl (meth) acrylate, (meth) acrylic acid, α-bromo (meth) acrylic acid , Α-Chlor (me ) Acrylic acid, β-furyl (meth) acrylic acid, β-styryl (meth) acrylic acid, maleic acid, maleic anhydride, maleic acid monoester (monomethyl maleate, monoethyl maleate, monoisopropyl maleate, etc.), Examples include fumaric acid, cinnamic acid, α-cyanocinnamic acid, itaconic acid, crotonic acid, and propiolic acid. The binder polymer may be a homopolymer of these monomers or a copolymer comprising two or more of these monomers, and the type of copolymerization in the latter case is not particularly limited.
[0020]
Examples of the (meth) acrylic acid alkyl ester include the following formula (III):
[Chemical 3]
CH₂= C (R₁₁) -COOR₁₂              (III)
(Wherein R₁₁Represents a hydrogen atom or a methyl group, R₁₂Represents an alkyl group having 1 to 12 carbon atoms. )
And compounds in which a hydroxyl group, an epoxy group, a halogen group or the like is substituted on the alkyl group of these compounds. R in this formula (III)₁₂Examples of the alkyl group having 1 to 12 carbon atoms represented by: methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group and These structural isomers are mentioned. Examples of the monomer represented by the formula (III) include (meth) acrylic acid methyl ester, (meth) acrylic acid ethyl ester, (meth) acrylic acid propyl ester, (meth) acrylic acid butyl ester, ( (Meth) acrylic acid pentyl ester, (meth) acrylic acid hexyl ester, (meth) acrylic acid heptyl ester, (meth) acrylic acid octyl ester, (meth) acrylic acid 2-ethylhexyl ester, (meth) acrylic acid nonyl ester, ( Examples include meth) acrylic acid decyl ester, (meth) acrylic acid undecyl ester, (meth) acrylic acid dodecyl ester, and the like. These can be used alone or in combination of two or more.
[0021]
In addition, the (A) binder polymer in the present invention preferably contains a carboxyl group from the standpoint of alkali developability in the case of a resist for circuit formation, for example, a polymerizable monomer having a carboxyl group and others. It can manufacture by radically polymerizing the polymerizable monomer. Furthermore, this binder polymer preferably contains styrene or a styrene derivative as a polymerizable monomer from the viewpoint of flexibility.
[0022]
In order to contain the above styrene or styrene derivative as a copolymerization component and to improve both the adhesion and release properties, the copolymer should contain 0.1% by weight or more of styrene or styrene derivative from the viewpoint of adhesion. Preferably, the content is preferably 30% by weight or less, more preferably 1 to 28% by weight, and particularly preferably 1.5 to 27% by weight from the viewpoint of release characteristics (size of release piece and release time).
[0023]
These binder polymers are used alone or in combination of two or more. As a binder polymer in the case of using two or more types in combination, for example, two or more types of binder polymers composed of different copolymerization components, two or more types of binder polymers having different weight average molecular weights, and two or more types of binder polymers having different degrees of dispersion Examples thereof include a binder polymer.
[0024]
Examples of the photopolymerizable compound (B) having at least one polymerizable ethylenically unsaturated bond in the molecule include compounds obtained by reacting a polyhydric alcohol with an α, β-unsaturated carboxylic acid, 2 , 2-bis (4-((meth) acryloxypolyethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxypolypropoxy) phenyl) propane, 2,2-bis (4- ( (Meth) acryloxypolybutoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxypolyethoxypolypropoxy) phenyl) propane and other bisphenol A-based (meth) acrylate compounds, glycidyl group-containing compounds Compounds obtained by reacting α, β-unsaturated carboxylic acids, (meth) acrylate compounds having urethane bonds in the molecule, etc. Retan monomer, nonylphenoxypolyethyleneoxyacrylate, γ-chloro-β-hydroxypropyl-β '-(meth) acryloyloxyethyl-o-phthalate, β-hydroxyalkyl-β'-(meth) acryloyloxyalkyl-o-phthalate Phthalic acid compounds such as (meth) acrylic acid alkyl ester, etc., but it is recommended that a bisphenol A (meth) acrylate compound or a (meth) acrylate compound having a urethane bond in the molecule be an essential component. It is preferable in terms of plating properties and adhesion. These may be used alone or in combination of two or more.
[0025]
Examples of the compound obtained by reacting the polyhydric alcohol with an α, β-unsaturated carboxylic acid include, for example, polyethylene glycol di (meth) acrylate having 2 to 14 ethylene groups and 2 to 2 propylene groups. Polypropylene glycol di (meth) acrylate being 14, polyethylene polyethylene glycol di (meth) acrylate having 2 to 14 ethylene groups and 2 to 14 propylene groups, trimethylolpropane di (meth) acrylate, Trimethylolpropane tri (meth) acrylate, EO-modified trimethylolpropane tri (meth) acrylate, PO-modified trimethylolpropane tri (meth) acrylate, EO, PO-modified trimethylolpropane tri (meth) acrylate, tetramethylolmethanetri (me ) Acrylate, tetramethylolmethane tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate and the like. Here, EO represents ethylene oxide, and the EO-modified compound has an ethylene oxide group block structure. PO represents propylene oxide, and the PO-modified compound has a block structure of propylene oxide groups.
[0026]
Examples of the 2,2-bis (4-((meth) acryloxypolyethoxy) phenyl) propane include 2,2-bis (4-((meth) acryloxydiethoxy) phenyl) propane, 2,2 -Bis (4-((meth) acryloxytriethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxytetraethoxy) phenyl) propane, 2,2-bis (4-((meta ) Acryloxypentaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxyhexaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxyheptaethoxy) phenyl) Propane, 2,2-bis (4-((meth) acryloxyoctaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxynona) Toxi) phenyl) propane, 2,2-bis (4-((meth) acryloxydecaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxyundecaethoxy) phenyl) propane, 2 , 2-bis (4-((meth) acryloxydodecaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxytridecaethoxy) phenyl) propane, 2,2-bis (4- ((Meth) acryloxytetradecaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxypentadecaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxy) Hexadecaethoxy) phenyl) propane and the like. 2,2-bis (4- (methacryloxypentaethoxy) phenyl) propane is commercially available as BPE-500 (manufactured by Shin-Nakamura Chemical Co., Ltd., product name). 4- (Methacryloxypentadecaethoxy) phenyl) propane is commercially available as BPE-1300 (manufactured by Shin-Nakamura Chemical Co., Ltd., product name). These may be used alone or in combination of two or more.
[0027]
Examples of the 2,2-bis (4-((meth) acryloxypolyethoxypolypropoxy) phenyl) propane include 2,2-bis (4-((meth) acryloxydiethoxyoctapropoxy) phenyl) propane. 2,2-bis (4-((meth) acryloxytetraethoxytetrapropoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxyhexaethoxyhexapropoxy) phenyl) propane and the like. . These may be used alone or in combination of two or more.
[0028]
Examples of the (meth) acrylate compound having a urethane bond in the molecule include, for example, a (meth) acryl monomer having an OH group at the β-position, isophorone diisocyanate, 2,6-toluene diisocyanate, 2,4-toluene diisocyanate, 1, 6-reaction products with diisocyanate compounds such as hexamethylene diisocyanate, tris ((meth) acryloxytetraethylene glycol isocyanate) hexamethylene isocyanurate, EO-modified urethane di (meth) acrylate, EO, PO-modified urethane di (meth) acrylate, etc. Is mentioned. Examples of the EO-modified urethane di (meth) acrylate include UA-11 (manufactured by Shin-Nakamura Chemical Co., Ltd., product name). Examples of EO and PO-modified urethane di (meth) acrylate include UA-13 (manufactured by Shin-Nakamura Chemical Co., Ltd., product name).
[0029]
Examples of the nonylphenoxypolyethyleneoxyacrylate include nonylphenoxytetraethyleneoxyacrylate, nonylphenoxypentaethyleneoxyacrylate, nonylphenoxyhexaethyleneoxyacrylate, nonylphenoxyheptaethyleneoxyacrylate, nonylphenoxyoctaethyleneoxyacrylate, nonylphenoxynonaethylene Examples include oxyacrylate, nonylphenoxydecaethyleneoxyacrylate, and nonylphenoxyundecaethyleneoxyacrylate.
[0030]
Examples of the (C) photopolymerization initiator include 2,4,5-triarylimidazole dimer or a derivative thereof; benzophenone, N, N′-tetramethyl-4,4′-diaminobenzophenone (Michler ketone), N, N′-tetraethyl-4,4′-diaminobenzophenone, 4-methoxy-4′-dimethylaminobenzophenone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1,2-ethylanthraquinone , Aromatic ketones such as phenanthrenequinone; benzoin ether compounds such as benzoin methyl ether, benzoin ethyl ether and benzoin phenyl ether; benzoin compounds such as methyl benzoin and ethyl benzoin; benzyl derivatives such as benzyl dimethyl ketal; 9-phenylacridine 1,7-bis (9,9'-acridinyl) acridine derivatives such as hexane and heptane; and N- phenylglycine, and the like. These may be used alone or in combination of two or more.
[0031]
Among these (C) photopolymerization initiators, it is preferable to use 2,4,5-triarylimidazole dimer or a derivative thereof from the viewpoint of less contamination of the solder plating bath and economically. . Here, the aryl group is a halogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, an aryl group having 6 to 14 carbon atoms, an amino group, an alkylamino group having 1 to 10 carbon atoms, A nitro group, a cyano group, a mercapto group, an alkyl mercapto group having 1 to 10 carbon atoms, a dialkylamino group having 2 to 20 carbon atoms, an allyl group, a hydroxyalkyl group having 1 to 20 carbon atoms, and an alkyl group having 1 to 1 carbon atoms. It may be substituted with one or more substituents such as a carboxyalkyl group having 10 carbon atoms, an acyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or a group containing a heterocyclic ring. Further, the substituents of the aryl groups of two 2,4,5-triarylimidazoles may give the same target compound or differently give asymmetric compounds. These 2,4,5-triarylimidazole dimers are used alone or in combination of two or more.
[0032]
Specific examples of 2,4,5-triarylimidazole dimer include 2,2′-bis (o-chlorophenyl) -4,5,4 ′, 5′-tetraphenyl-1,2′-biimidazole. 2- (o-chlorophenyl) -4,5-diphenylimidazole dimer, 2,2'-bis (o-chlorophenyl) -4,4 ', 5,5'-tetra (p-chlorophenyl) imidazole dimer 2- (o-chlorophenyl) -4,5-di (m-methoxyphenyl) imidazole dimer, 2,2'-bis (o-chlorophenyl) -4,4 ', 5,5'-tetra ( p-fluorophenyl) imidazole dimer, 2,2′-bis (o-bromophenyl) -4,4 ′, 5,5′-tetra (o-chloro-p-methoxyphenyl) imidazole dimer, 2 , 2'-bis (o-chrome Phenyl) -4,4 ', 5,5'-tetra (o, p-dichlorophenyl) imidazole dimer, 2,2'-bis (o-chlorophenyl) -4,4', 5,5'-tetra ( o, p-dibromophenyl) imidazole dimer, 2,2′-bis (o-chlorophenyl) -4,4 ′, 5,5′-tetra (p-chloronaphthyl) imidazole dimer, 2,2 ′ -Bis (m, p-dichlorophenyl) -4,4 ', 5,5'-tetraphenylimidazole dimer, 2,2'-bis (o, p-dichlorophenyl) -4,4', 5,5 ' -Tetraphenylimidazole dimer, 2,2'-bis (o, p-dichlorophenyl) -4,4 ', 5,5'-tetra (o, p-dichlorophenyl) imidazole dimer, 2- (o- Fluorophenyl) -4,5-dipheni Imidazole dimer, 2- (o-methoxyphenyl) -4,5-diphenylimidazole dimer, 2- (p-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, 2,2'-bis (p-bromophenyl) -4,4 ', 5,5'-tetraphenylimidazole dimer, 2,2'-bis (o-bromophenyl) -4,4 ', 5,5'-tetra (o, p-dichlorophenyl) imidazole dimer, 2,2'-bis (o-bromophenyl) -4,4', 5,5'-tetra (p-iodophenyl) I Midazole dimer, 2,2'-bis (m-bromophenyl) -4,4 ', 5,5'-tetraphenylimidazole dimer, 2,2'-bis (m, p-dibromophenyl)- 4,4 ', 5,5'-tetraphenylimidazole dimer and the like. The aryl group of these compounds may be substituted with one or more substituents as described above, such as a halogen atom, an alkyl group having 1 to 20 carbon atoms, etc., and these substituents give the same target compound. Alternatively, differently asymmetric compounds may be provided.
[0033]
In order to dissolve these 2,4,5-triarylimidazole dimers and derivatives thereof, it is preferable to use, for example, methanol and toluene as a solvent. Specifically, the following methods (1) and (2) Is mentioned.
[0034]
(1) Toluene is mixed in a mixed solution of methanol and 2,4,5-triarylimidazole dimer. Here, the blending amount of methanol is preferably 0.1 times or more, more preferably 1 to 10 times that of 2,4,5-triarylimidazole dimer in terms of weight ratio. Moreover, the compounding amount of toluene is preferably 0.2 times or more, more preferably 2 to 20 times that of 2,4,5-triarylimidazole dimer in terms of weight ratio.
[0035]
(2) Mix methanol, toluene, and 2,4,5-triarylimidazole dimer. Here, the blending amount of methanol and toluene is preferably 0.5 times or more, more preferably 2 to 10 times that of 2,4,5-triarylimidazole dimer in weight ratio. .
[0036]
Methanol and toluene dissolve the 2,4,5-triarylimidazole dimer and its derivative well, and the 2,4,5-triarylimidazole dimer and / or its derivative dissolved both as solvents. When it mix | blends as a photoinitiator of a photosensitive resin composition, in the photosensitive resin composition which has a wide composition, there exists a tendency to suppress the variation in photosensitivity. In addition, other solvents may be added as long as the solubility of the 2,4,5-triarylimidazole dimer and its derivatives is not impaired, but 60% by weight or more of the total solvent is methanol and toluene. preferable.
[0037]
  As the (D) hindered amine compound, a hindered amine compound having a piperidine skeleton represented by the following formula (I) is used from the viewpoint of suppressing the increase in sensitivity and changes over time and maintaining a good balance of adhesion and resolution. Using a dartamine compoundThe
[0038]
[Formula 4]

(Wherein R₁, R₂, R₃, R₄Each independently represents an alkyl group having 1 to 20 carbon atoms.. )
[0039]
  thislike(D) As a hindered amine compoundIsCompound represented by the following formula (II)Usebe able to.
[0040]
[Chemical formula 5]

(Wherein R_FiveIs a hydrogen atom or a methyl group, X is an oxygen atom or -NH-, Y is an alkylene group having 0 to 10 carbon atoms or an alkyleneoxy group having 2 to 6 carbon atoms, R_TenRepresents an alkyl group having 1 to 20 carbon atoms. R₆, R₇, R₈, R₉Each independently represents an alkyl group having 1 to 20 carbon atoms. )
In the formula (II), an alkyleneoxy group having 2 to 6 carbon atoms (—RO—; R is an alkylene group having 2 to 6 carbon atoms) of Y is particularly an ethyleneoxy group having 2 carbon atoms (—C₂H_FourO-) is preferred.
[0041]
Examples of the hindered amine compound represented by the formula (II) include 2,2,6,6, -tetramethyl-4-piperidyl acrylate, 1,2,2,6,6, -pentamethyl-4-piperidyl acrylate. Late, N- (2,2,6,6, -tetramethyl-4-piperidyl) acrylamide, N- (1,2,2,6,6, -pentamethyl-4-piperidyl) acrylamide, 2,2 , 6,6, -tetramethyl-4-piperidylmethacrylate, 1,2,2,6,6, -pentamethyl-4-piperidylmethacrylate, N- (2,2,6,6,- Tetramethyl-4-piperidyl) methacrylamide, N- (1,2,2,6,6, -pentamethyl-4-piperidyl) methacrylamide, 2- (1,2,2,6,6, -pentamethyl-4 -Piperidyloxy) ethyl (me ) Acrylate - door, and the like.
[0042]
  Of the compounds exemplified above, the solubility in the photosensitive resin composition during the production of the photosensitive elementAnd 2, 2,6,6, -tetramethyl-4-piperidyl methacrylate, 1,2,2,6,6, -pentamethyl-4-piperidyl methacrylate, 2- (1,2,2,6 , 6, -pentamethyl-4-piperidyl) ethyl methacrylate and 2- (1,2,2,6,6, -pentamethyl-4-piperidyloxy) ethyl methacrylate are preferably used. Particularly preferred is 2,2,6,6, -tetramethyl-4-piperidyl methacrylate because of its excellent adhesion and resolution.
  In addition, the above formula ( II ) And a hindered amine compound having a piperidine skeleton represented by formula (I) can be used in combination with these hindered amine compounds. Examples of these hindered amine compounds include bis (2,2,6,6, -tetramethyl). -4-piperidyl) sebacate, bis (1,2,2,6,6, -pentamethyl-4-piperidyl) sebacate, 1- [2- [3- (3,5-di-tert-butyl-4-hydroxy) Phenyl) propionyloxy] ethyl] -4- [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy-2,2,6,6, -tetramethylpiperidine, 8-benzyl -7,7,9,9-tetramethyl-3-octyl-1,3,8-triazaspiro [4,5] undecane-2,4-dione, 4-benzo Luoxy-2,2,6,6, -tetramethylpiperidine, dimethyl-1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6 succinate, -tetramethyl-piperidine polycondensate, etc. Can be mentioned. Of these, bis (2,2,6,6, -tetramethyl-4-piperidyl) sebacate is preferable from the viewpoint of solubility in the photosensitive resin composition during the production of the photosensitive element.
[0043]
Next, the preferable compounding quantity of the above components (A)-(D) is demonstrated. The blending amount of the (A) binder polymer is such that the hardness (brittleness) of the photocured product and the film formability when used as a photosensitive element with respect to 100 parts by weight of the total amount of the components (A) and (B). From the viewpoint, it is preferably 40 parts by weight or more, from the viewpoint of photosensitivity, preferably 80 parts by weight or less, and more preferably 45 to 70 parts by weight.
[0044]
The blending amount of the (B) photopolymerizable compound is preferably 20 parts by weight or more from the viewpoint of photosensitivity with respect to 100 parts by weight of the total amount of the components (A) and (B), and the hardness of the photocured product From the viewpoint of (brittleness), it is preferably 60 parts by weight or less, and more preferably 30 to 55 parts by weight.
[0045]
The blending amount of the (C) photopolymerization initiator is preferably 0.1 parts by weight or more from the viewpoint of photosensitivity with respect to 100 parts by weight of the total amount of the components (A) and (B). In view of the above, it is preferably 20 parts by weight or less, and more preferably 0.2 to 10 parts by weight. When this amount exceeds 20 parts by weight, absorption on the surface of the composition increases during exposure, and internal photocuring tends to be insufficient.
[0046]
The blending amount of the component (D) is 0.001 part by weight or more from the viewpoint of an increase in sensitivity and an effect of suppressing changes over time with respect to a total amount of 100 parts by weight of the component (A), the component (B) and the component (C) Preferably, it is 10 parts by weight or less from the viewpoint of adhesion, and more preferably 0.005 to 5 parts by weight.
[0047]
In addition to the above essential four components, the photosensitive resin composition of the present invention includes, as necessary, a dye such as malachite green, a photochromic agent such as tribromophenylsulfone, leucocrystal violet, a thermochromic inhibitor, Plasticizers such as p-toluenesulfonamide, pigments, fillers, antifoaming agents, flame retardants, stabilizers other than the above (D) hindered amine compounds, adhesion imparting agents, leveling agents, peeling accelerators, antioxidants, perfumes In addition, an imaging agent, a thermal crosslinking agent and the like can be contained in an amount of about 0.01 to 20 parts by weight with respect to 100 parts by weight of the total amount of the component (A) and the component (B). These can be used alone or in combination of two or more.
[0048]
If necessary, the photosensitive resin composition of the present invention is a solvent such as methanol, ethanol, acetone, methyl ethyl ketone, methyl cellosolve, ethyl cellosolve, toluene, N, N-dimethylformamide, propylene glycol monomethyl ether, or a mixed solvent thereof. And can be applied as a solution having a solid content of about 30 to 60% by weight. The use is not particularly limited, but it is liquid on the surface of a metal surface, for example, an iron-based alloy such as copper, copper-based alloy, nickel, chromium, iron, stainless steel, preferably copper, copper-based alloy, iron-based alloy. After applying as a resist and drying, it is preferably used by coating with a protective film, if necessary, or in the form of a photosensitive element.
[0049]
Although the thickness of the photosensitive resin composition layer to be applied varies depending on the use, it is preferably 1 μm or more from the viewpoint of ease of industrial coating, after drying, from the viewpoint of adhesive strength and resolution. It is preferable that it is 100 micrometers or less, and it is more preferable that it is about 1-50 micrometers. Further, the obtained photosensitive resin composition layer preferably has a transmittance for ultraviolet rays having a wavelength of 365 nm of 5% or more from the viewpoint of adhesion, and preferably 75% or less from the viewpoint of resolution. 60% is more preferable, and 10 to 40% is particularly preferable. The transmittance can be measured by a UV spectrometer, and examples of the UV spectrometer include a 228A type W beam spectrophotometer manufactured by Hitachi, Ltd.
[0050]
Next, a photosensitive element according to the present invention, that is, a photosensitive element in which a resist layer made of the above-described photosensitive resin composition according to the present invention is formed on a support will be described with reference to the drawings.
[0051]
FIG. 1 schematically shows an embodiment of a photosensitive element. The photosensitive element 1 includes a support 11 and a resist layer (photosensitive resin composition layer) 12 formed thereon. Is included.
[0052]
As the support 11, for example, a polymer film having heat resistance and solvent resistance such as polyethylene terephthalate, polypropylene, polyethylene, and polyester can be preferably used. The thickness of the support is preferably 5 μm or more from the viewpoint of strength during peeling before development, preferably 25 μm or less from the viewpoint of resolution, more preferably 8 to 20 μm, and 10 to 16 μm. It is particularly preferred. Further, the haze of the support 11 is preferably 0.001% or more, preferably 5.0% or less from the viewpoint of resolution, more preferably 0.001 to 2.0%, It is especially preferable that it is 0.01 to 1.8%. The haze is measured according to JIS K 7105, and can be measured with a commercially available turbidimeter such as NDH-1001DP (trade name, manufactured by Nippon Denshoku Industries Co., Ltd.).
[0053]
Although the formation method of the resist layer 12 on the support body 11 is not specifically limited, It can obtain preferably by apply | coating and drying the solution of the photosensitive resin composition. The thickness of the resist layer to be applied varies depending on the application, but as described above, the thickness after drying is preferably about 1 to 100 μm, and more preferably about 1 to 50 μm. The coating can be performed by a known method such as a roll coater, a comma coater, a gravure coater, an air knife coater, a die coater, or a bar coater. Drying can be performed at 50 to 200 ° C. for about 0.5 to 20 minutes, preferably at 80 to 160 ° C. for about 1 to 10 minutes. The amount of the remaining organic solvent in the resist layer 12 is preferably 2% by weight or less from the viewpoint of preventing the organic solvent from diffusing in the subsequent step.
[0054]
The resist layer surface of the photosensitive element 1 is preferably covered with a protective film (not shown) made of a polymer film such as polyethylene or polypropylene. The thickness of the protective film is preferably 5 μm or more from the viewpoint of strength at the time of lamination, preferably 30 μm, more preferably 10 to 28 μm, and more preferably 15 to 25 from the viewpoint of inexpensiveness. Is particularly preferred.
[0055]
The tensile strength in the longitudinal direction of the protective film is preferably 13 MPa or more, more preferably 13 to 100 MPa, still more preferably 14 to 100 MPa, from the viewpoint of strength during lamination. 100 MPa is very preferable, and 16 to 100 MPa is very preferable. In addition, the tensile strength in the width direction is preferably 9 MPa or more, more preferably 9 to 100 MPa, further preferably 10 to 100 MPa, from the viewpoint of strength during lamination. It is very preferable that it is 12 to 100 MPa. Here, the tensile strength can be measured in accordance with JIS C 2318-1997 (5.3.3), for example, a commercial tensile strength tester such as a trade name Tensilon manufactured by Toyo Baldwin Co., Ltd. Measurement is possible.
[0056]
Since these support and protective film must be removable from the resist layer later, they must not be surface-treated so that they cannot be removed. It may be given. For example, these supports and protective films may be subjected to antistatic treatment as necessary. In addition, it is preferable to select one having a smaller adhesive force between the resist layer and the protective film than an adhesive force between the resist layer and the support.
[0057]
A photosensitive element having a two-layer or three-layer structure composed of a support, a resist layer, and a protective film as necessary is not shown in the drawing, but a cushion layer, an adhesive layer, a light absorption layer, a gas barrier. An intermediate layer such as a layer or a protective layer may be provided.
[0058]
The photosensitive element thus obtained is stored, for example, as it is or by further laminating a protective film on the surface of the resist layer and winding it around a cylindrical winding core.
[0059]
Another photosensitive element of the present invention includes a support and a resist layer that is coated on the support and dried at 80 ° C. or higher.
[0060]
As the support, those similar to those described in the above photosensitive element can be preferably used. The resist layer is not particularly limited as long as it can withstand a drying temperature of 80 ° C. or higher and does not cause a problem such as an increase in sensitivity due to heat in the drying process or a change with time. As an example, the photosensitive resin composition of the present invention can be preferably used.
[0061]
The resist layer can be applied by a known method such as a roll coater, a comma coater, a gravure coater, an air knife coater, a die coater, or a bar coater. Although the thickness of the resist layer to be applied varies depending on the application, the thickness after drying is preferably about 1 to 100 μm, and more preferably about 1 to 50 μm.
[0062]
The applied resist layer is dried at 80 ° C. or higher, preferably at 80 to 200 ° C. for about 0.5 to 20 minutes, more preferably at 80 to 160 ° C. for about 1 to 10 minutes. The amount of the remaining organic solvent in the resist layer is preferably 2% by weight or less from the viewpoint of preventing the organic solvent from diffusing in the subsequent step.
[0063]
The surface of the formed resist layer is preferably covered with a protective film, and as the protective film, the same materials as described in the above photosensitive element can be preferably used. About the structure of the other photosensitive element, it is the same as that of having described about the above-mentioned photosensitive element.
[0064]
Next, a resist pattern manufacturing method according to the present invention will be described with reference to FIG. 2 schematically showing an example of the process.
[0065]
First, as process (i), the resist layer which consists of the photosensitive resin composition of this invention mentioned above is laminated | stacked on the board | substrate (circuit formation board | substrate) 2. FIG. Although the lamination method is arbitrary, for example, as shown in FIG. 2A, the photosensitive element 1 described above is laminated on the substrate 2 so that the resist layer 12 is in close contact with the surface of the substrate 2. Prior to the lamination, when a protective film (not shown) exists on the resist layer 12 of the photosensitive element 1, the protective film is removed. As this lamination method, for example, while heating the resist layer 12 to about 70 to 130 ° C., about 0.1 to 1 MPa (1 to 10 kgf / cm) is applied to the substrate 2.²And a method of laminating by pressure bonding at a pressure of about). From the viewpoint of adhesion and followability, it is preferable to laminate under reduced pressure. In addition, as a board | substrate, what has a to-be-processed layer which consists of metals, such as copper, on the base which consists of a glass fiber epoxy resin etc., for example, The surface of the board | substrate 2 laminated | stacked is a metal surface normally, There is no particular limitation. If the resist layer is heated to 70 to 130 ° C. as described above, it is not necessary to pre-heat the substrate in advance, but the substrate can be pre-heated in order to further improve the stackability.
[0066]
After the lamination of the resist layer is completed, as the step (ii), an actinic ray is irradiated in an image shape to photocur the resist layer in the exposed portion. As a method of irradiating actinic rays in an image form, for example, as shown in FIG. 2 (B), the resist layer 12 is irradiated with an actinic ray through a negative or positive mask pattern 3 called an artwork, The resist layer 12 in the exposed portion can be photocured. As the light source for actinic light, a known light source such as a carbon arc lamp, a mercury vapor arc lamp, an ultra-high pressure mercury lamp, a high-pressure mercury lamp, or a xenon lamp that emits ultraviolet rays effectively is used. Moreover, what emits visible light effectively, such as a photographic flood light bulb and a solar lamp, is also used. Further, laser direct drawing exposure can be performed without using a mask pattern. The exposure in the step (ii) can be performed in the state where the support 11 is present as long as the light irradiation to the resist layer 12 is not hindered (for example, when the support is transparent).
[0067]
After the exposure, when a support is present on the photosensitive resin composition layer, after removing the support, as a step (iii), the resist layer in the unexposed area is selectively removed by development. As a result, a resist pattern 121 is formed as shown in FIG. Development is performed by wet development, dry development, etc. In the case of wet development, using a developer corresponding to the composition of the resist layer, such as an alkaline aqueous solution, an aqueous developer, an organic solvent, etc., a dip method, rocking immersion It is performed by a known method such as a method, a battle method, a spray method, brushing, or slapping. Among them, the high pressure spray method is most suitable for improving the resolution. Moreover, you may use together 2 or more types of image development methods as needed.
[0068]
As the developing solution, a safe and stable solution having good operability such as an alkaline aqueous solution is used. 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, potassium or ammonium carbonate or bicarbonate; potassium phosphate, phosphoric acid Examples include alkali metal phosphates such as sodium; alkali metal pyrophosphates such as sodium pyrophosphate and potassium pyrophosphate. Among them, for example, a dilute solution of 0.1 to 5 wt% sodium carbonate, a dilute solution of 0.1 to 5 wt% potassium carbonate, a dilute solution of 0.1 to 5 wt% sodium hydroxide, 0.1 to 5 A dilute solution of weight% sodium tetraborate is preferred. The pH of the alkaline aqueous solution is preferably in the range of 9 to 11, and the temperature is adjusted according to the developability of the photosensitive resin composition layer. In the alkaline aqueous solution, a surfactant, an antifoaming agent, a small amount of an organic solvent for accelerating development, and the like may be mixed.
[0069]
The aqueous developer comprises water or an alkaline aqueous solution and one or more organic solvents. Examples of the alkaline substance include borax, sodium metasilicate, tetramethylammonium hydroxide, ethanolamine, ethylenediamine, diethylenetriamine, 2-amino-2-hydroxymethyl-1,3-propanediol, 1 , 3-diaminopropanol-2, morpholine and the like. The pH of the developer is preferably as low as possible within the range where the resist can be sufficiently developed, preferably pH 8-12, and more preferably pH 9-10. Examples of the organic solvent include triacetone alcohol, acetone, ethyl acetate, alkoxyethanol having an alkoxy group having 1 to 4 carbon atoms, ethyl alcohol, isopropyl alcohol, butyl alcohol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono And butyl ether. These may be used alone or in combination of two or more. The concentration of the organic solvent is usually preferably 2 to 90% by weight, and the temperature can be adjusted according to the developability. Further, a small amount of a surfactant, an antifoaming agent and the like can be mixed in the aqueous developer.
[0070]
Examples of the organic solvent developer used alone include 1,1,1-trichloroethane, N-methylpyrrolidone, N, N-dimethylformamide, cyclohexanone, methyl isobutyl ketone, and γ-butyrolactone. These organic solvents preferably add water in the range of 1 to 20% by weight in order to prevent ignition.
[0071]
As processing after development, heating at about 60 to 250 ° C. or 0.2 to 10 J / cm as necessary²The resist pattern formed may be further cured by performing exposure to a certain extent.
[0072]
Next, a method for manufacturing a printed wiring board according to the present invention will be described with reference to FIGS. 3 and 4 schematically showing an example of the process.
[0073]
The steps until the resist pattern is formed are the same as those described in the above resist pattern manufacturing method including the (i) laminating step, (ii) exposing step, and (iii) developing step. Regarding the subsequent circuit formation step (iv), FIG. 3 shows a subtractive method using etching, and FIG. 4 shows a semi-additive method using plating.
[0074]
After the resist pattern 121 is formed, as a step (iv), as shown in FIG. 3B, a substrate (circuit forming substrate) having a layer 21 to be processed on the surface using the formed resist pattern 121 as a mask. The processed layer 21 of 2 is etched, or as shown in FIG. 4B, plating is selectively performed on the processed layer 21 to form a plated layer 22 made of copper or the like. For example, a cupric chloride solution, a ferric chloride solution, an alkaline etching solution, or a hydrogen peroxide-based etching solution can be used for etching the processing layer 21 made of a metal surface in FIG. It is desirable to use a ferric chloride solution because it has a good etch factor. 4B, for example, copper plating such as copper sulfate plating and copper pyrophosphate plating, solder plating such as high-throw solder plating, watt bath (nickel sulfate-nickel chloride) plating, nickel sulfamate There are nickel plating such as plating, gold plating such as hard gold plating and soft gold plating.
[0075]
Finally, as shown in FIGS. 3 (C) and 4 (C), the resist pattern 121 remaining on the substrate 2 is peeled off with, for example, a stronger alkaline aqueous solution than the alkaline aqueous solution used for development, The printed wiring board 4 in which the circuit 211 is formed can be obtained. In the case of the semi-additive method, as shown in FIG. 4D, after the resist pattern 121 is removed, the underlying layer 21 is also removed by, for example, a quick etching method. As the strong alkaline aqueous solution, for example, a 1 to 10% by weight sodium hydroxide aqueous solution, a 1 to 10% by weight potassium hydroxide aqueous solution and the like are used. Examples of the peeling method include a dipping method and a spray method, and the dipping method and the spray method may be used alone or in combination. The printed wiring board on which the resist pattern is formed may be a multilayer printed wiring board.
[0076]
【Example】
  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples without departing from the technical idea of the present invention.
[Examples 1-4, Reference Example 5And Comparative Examples 1 to 3]
  The materials shown in Table 1 were blended to obtain photosensitive resin composition solutions # 1 to # 5.
[0077]
[Table 1]

* 1: 2,2-bis (4- (methacryloxypentaethoxy) phenyl) propane, manufactured by Shin-Nakamura Chemical Co., Ltd.
* 2: EO-modified nonylphenyl acrylate (repeating unit of ethylene glycol chain is 8), manufactured by Kyoeisha Chemical Co., Ltd.
* 3: Polypropylene glycol diacrylate (repeat unit of propylene glycol chain is 6-7), manufactured by Shin-Nakamura Chemical Co., Ltd.
* 4: 2,2,6,6, -tetramethyl-4-piperidyl methacrylate, manufactured by Hitachi Chemical Co., Ltd.
* 5: Bis (2,2,6,6, -tetramethyl-4-piperidyl) sebacate, manufactured by Sankyo Co., Ltd.
* 6: Hydroquinone monomethyl ether, manufactured by Seiko Chemical Co., Ltd.
[0078]
  Next, the obtained photosensitive resin composition solution was uniformly applied onto a 16 μm-thick polyethylene terephthalate film (haze: 1.7%, trade name: GS-16, manufactured by Teijin Ltd.), and hot air convection type It dried on the predetermined conditions shown in Table 2 using the dryer. Thereafter, the surface of the obtained photosensitive resin composition layer (resist layer) was coated with a protective film made of polyethylene (tensile strength in the film longitudinal direction: 16 MPa, tensile strength in the film width direction: 12 MPa, trade name: NF-15, Protected by Tamapoli Co., Ltd.Examples 1-4, Reference Example 5And the photosensitive element of Comparative Examples 1-3 was obtained. The thickness of the resist layer after drying was 50 μm in all cases.
[0079]
[Table 2]

[0080]
After fabrication, the following characteristics were measured for each photosensitive element after 4 hours and 30 days in a light-shielded state at 23 ° C. ± 2 ° C. RH 60%. In the evaluation of various properties, a copper-clad laminate (made by Hitachi Chemical Co., Ltd., trade name MCL-E-61), which is a glass epoxy material laminated with copper foil (thickness 35 μm) on both sides, is heated to 80 ° C. The photosensitive element obtained on the copper surface was laminated at a speed of 3 m / min using a 120 ° C. heat roll while peeling off the protective film on the resist layer. Prior to the lamination of the photosensitive element, the copper surface of the copper-clad laminate was polished using a polishing machine (manufactured by Sankei Co., Ltd.) having a brush equivalent to # 600, washed with water, and then dried with an air flow. .
[0081]
Next, using an exposure machine (manufactured by Oak Co., Ltd.) HMW-201B having a high-pressure mercury lamp, a stove 21-step tablet as a negative was placed on the test piece, and 60 mJ / cm.²And exposed.
[0082]
<Sensitivity>
The polyethylene terephthalate film of the test piece was peeled off and sprayed with a 1% by weight aqueous sodium carbonate solution at 30 ° C. for 60 seconds to remove the unexposed portions, and then the number of steps of the step tablet of the photocured film formed on the copper-clad laminate Was measured to evaluate the photosensitivity of the photosensitive resin composition. The photosensitivity 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 photosensitivity.
[0083]
<Resolution>
A photo tool having a 21-step tablet of Stöffer and a photo tool having a wiring pattern with a line width / space width of 30/30 to 200/200 (unit: μm) as a negative for resolution evaluation are closely attached. The exposure was performed with an energy amount such that the number of steps remaining after development of the 21-step tablet was 8.0. The resolution was evaluated based on the smallest value of the space width between the line widths in which the unexposed portion could be removed cleanly by the development process. The smaller the numerical value, the better the resolution.
[0084]
<Plating resistance>
As described above, the following pretreatment was performed on the test piece laminated on the copper-clad laminate, exposed with a predetermined exposure amount, and then developed with the developer. First, it is immersed for 5 minutes in a degreasing bath (PC-455 (Meltex) 25% by weight), washed with water, and then immersed in a soft etching bath (ammonium persulfate 150 g / liter) for 2 minutes, washed with water, It was immersed in a 10% by weight sulfuric acid bath for 1 minute. The obtained test piece was placed in a copper sulfate plating bath (copper sulfate 75 g / liter, sulfuric acid 190 g / liter, chloride ion 50 ppm, copper grease PCM (Meltex) 5 ml / liter), and copper sulfate plating was performed at room temperature. 3A / dm²For 40 minutes.
[0085]
Thereafter, the test piece was washed with water and immersed in 10% by weight borohydrofluoric acid for 1 minute, and then a solder plating bath (45% by weight tin borofluoride 64 ml / liter, 45% by weight lead borofluoride 22 ml / liter, 42% by weight) % Borohydrofluoric acid 200 ml / liter, Plutin LA conductivity salt (Meltex) 20 g / liter, Plutin LA starter (Meltex) 41 ml / liter) and solder plating at room temperature. 5A / dm²For 15 minutes.
[0086]
After the test piece was washed with water and dried, a 90 ° peel-off test was immediately performed to examine the plating resistance of the test piece. The 90 ° peel-off test is a process in which a cellophane tape is applied to a substrate that has been plated, and is adhered closely with a rubber roller. This is peeled off immediately at a peel angle of 90 ° C, and the degree of resist transfer to the cellophane tape is observed. is there. Further, after the 90 ° peel-off test, the resist was peeled off, and the presence or absence of solder plating was observed from above using an optical microscope, a projector, or the like. In the case where solder plating occurs, solder deposited by solder plating is observed below the transparent resist.
[0087]
<Adhesion>
Another test piece was subjected to a cross-cut test (JIS-K-5400) after exposure and development at an exposure amount of 8 steps with a stove 21-step tablet. In the cross-cut test, 11 parallel vertical and horizontal lines are drawn at 1 mm intervals in the center of a circuit forming substrate on which photosensitive elements are laminated using a cutter guide.²This is done by making a grid-like cut so that 100 squares can be formed, and evaluating the state of the wound. For the cut, the cutting edge of the cutter knife is kept at a constant angle in the range of 35 to 45 degrees with respect to the photosensitive element, and 0.5 seconds per cut so as to reach the circuit forming substrate through the resist layer. It was pulled at a constant speed. The evaluation of the state of the wound is as follows.
[0088]
10 points: Each of the cuts is thin, both sides are smooth, and the intersection of the cuts and the square do not peel off at a glance.
8 points: There is a slight peeling at the intersection of the cuts, but there is no peeling at a glance of the square, and the area of the missing part is within 5% of the total square area.
6 points: There is peeling between both sides of the cut and the intersection, and the area of the missing part is 5 to 15% of the total square area.
Four points: The width of the peeling due to the cut is wide, and the area of the missing part is 15 to 35% of the total square area.
2 points: The width of the peeling due to the cut is wider than 4 points, and the area of the missing part is 35 to 65% of the total square area.
0 point: The area of the missing part is 65% or more of the total square area.
The results obtained above are shown in Tables 3 and 4.
[0089]
[Table 3]

[0090]
[Table 4]

[0091]
  As is apparent from Tables 3 and 4, Examples 1 to4Then, even if the drying temperature at the time of preparation of the photosensitive element was high, the increase in sensitivity was suppressed, and no change was observed after 30 days. In addition, the resolution, cross-cut property (adhesiveness), and plating resistance of the resist layers of the examples were all good.
[0092]
[Reference Example 1]
To a mixed solution of 3.0 g of methanol and 3.0 g of 2- (o-chlorophenyl) -4,5-diphenylimidazole dimer, 6.0 g of toluene was blended to obtain a solution.
[0093]
[Reference Example 2]
A solution was obtained by mixing 6.0 g of methanol, 6.0 g of toluene, and 3.0 g of 2,4,5-triarylimidazole dimer.
[0094]
[Reference Example 3]
10.0 g of acetone, 3.0 g of dimethylformamide, 7.0 g of toluene and 3.0 g of 2,4,5-triarylimidazole dimer were mixed to obtain a solution.
[0095]
The solubility of 2- (o-chlorophenyl) -4,5-diphenylimidazole dimer in the solutions obtained in Reference Examples 1 and 2 was superior to the solubility in the solution obtained in Reference Example 3. Moreover, the photosensitive resin composition which mix | blended the solution obtained in Reference Example 1 and 2 as a photoinitiator is more than the photosensitive resin composition which mix | blended the solution obtained in Reference Example 3 as a photoinitiator. There was a tendency to suppress variations in photosensitivity.
[0096]
【The invention's effect】
The photosensitive resin composition of the present invention can be dried at a high temperature when producing a photosensitive element, so that the drying time can be shortened and the sensitivity is stabilized, so that high productivity can be realized. Since it is excellent in resolution, adhesion and chemical resistance (plating resistance), it is particularly useful as a circuit forming resist for printed wiring.
[Brief description of the drawings]
FIG. 1 is a schematic view showing an embodiment of a photosensitive element according to the present invention.
FIG. 2 is a schematic diagram showing an example of a process for producing a resist pattern according to the present invention.
FIG. 3 is a schematic diagram showing an example of a process for producing a printed wiring board according to the present invention.
FIG. 4 is a schematic view showing one process example of a method for producing a printed wiring board according to the present invention.
[Explanation of symbols]
1 Photosensitive element
11 Support
12 resist layer (photosensitive resin composition layer)
2 Substrate (circuit forming substrate)
121 resist pattern
21 Work Layer
211 circuit
4 Printed wiring board

Claims (9)

Photosensitivity comprising (A) binder polymer, (B) photopolymerizable compound having at least one polymerizable ethylenically unsaturated bond in the molecule, (C) photopolymerization initiator, and (D) hindered amine compound. And a hindered amine compound represented by the following formula ( II ) as the component (D), which includes a 2,4,5-triarylimidazole dimer or a derivative thereof as the component (C) . A photosensitive resin composition comprising:

(In the formula, R ₅ is a hydrogen atom or a methyl group, X is an oxygen atom or —NH—, Y is an alkylene group having 0 to 10 carbon atoms or an alkyleneoxy group having 2 to 6 carbon atoms, and R ₁₀ is 1 to 1 carbon atoms. 20 represents an alkyl group, and R ₆ , R ₇ , R ₈ and R ₉ each independently represents an alkyl group having 1 to 20 carbon atoms.) The photosensitive resin composition according to claim 1, wherein the blending amount of the component (D) is 0.001 to 10 parts by weight with respect to 100 parts by weight of the total amount of the components (A), (B) and (C). object. The photosensitive element containing a support body and the resist layer which consists of the photosensitive resin composition of Claim 1 or Claim 2 formed on the said support body. The photosensitive element according to claim 3, wherein the resist layer is applied on the support and dried at 80 ° C. or higher. The photosensitive element according to claim 3, wherein a protective film is further laminated on the resist layer. A resist pattern manufacturing method including the following steps:
(I) a step of laminating a resist layer comprising the photosensitive resin composition according to claim 1 or 2 on a substrate;
(Ii) a step of irradiating the image with an actinic ray to photocur the resist layer in the exposed portion;
(Iii) A step of selectively removing the resist layer in an unexposed portion by development to form a resist pattern. The step (i) includes a photosensitive element in which a resist layer made of the photosensitive resin composition according to claim 1 or 2 is formed on a support, and the resist layer is the substrate. The method for producing a resist pattern according to claim 6, wherein the method is performed by laminating so as to be in close contact with the surface. A method for producing a printed wiring board including the following steps:
(I) A step of laminating a resist layer comprising the photosensitive resin composition according to claim 1 or 2 on the processed layer of a substrate having a processed layer on the surface;
(Ii) a step of irradiating the image with an actinic ray to photocur the resist layer in the exposed portion;
(Iii) a step of selectively removing the resist layer in an unexposed portion by development to form a resist pattern;
(Iv) A step of etching the processed layer of the substrate or selectively plating the processed layer of the substrate using the resist pattern as a mask. In the step (i), a photosensitive element having a resist layer formed of the photosensitive resin composition according to claim 1 or 2 formed on a support is formed on a substrate having a layer to be processed on the surface. The method for producing a printed wiring board according to claim 8, wherein the method is performed by laminating the resist layer so as to be in close contact with the surface of the layer to be processed of the substrate.

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