JP2004223842A

JP2004223842A - Screen process printing form plate and its manufacturing method

Info

Publication number: JP2004223842A
Application number: JP2003013453A
Authority: JP
Inventors: Masaru Manjiyu; 萬壽　　優
Original assignee: Murata Manufacturing Co Ltd
Current assignee: Murata Manufacturing Co Ltd
Priority date: 2003-01-22
Filing date: 2003-01-22
Publication date: 2004-08-12
Anticipated expiration: 2023-01-22
Also published as: JP4341250B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a screen process printing form plate wherein a film thickness in a printing area is uniform without arranging a dummy figure outside the printing area. <P>SOLUTION: A first metal film is formed by applying electrolytic plating by forming a penetration hole insulated film corresponding to a shape of the penetration hole onto a base material. Then, after forming a printing hole insulation film corresponding to a printing pattern shape on the first metal film and a dummy insulation film surrounding that at a distance of a specific interval from the printing hole insulation film, electrolytic plating is applied to form a second metal film. At that time, an interval between the printing hole insulation film and the dummy insulation film is more narrowed near an end part of the printing form plate than its central part. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、スクリーン印刷に用いられるスクリーン印刷版およびその製造方法に関し、特に、エレクトロフォーミング技法でスクリーン印刷版を作製する際のスクリーン印刷版の厚みの均一化に関する。
【０００２】
【従来の技術】
積層セラミックコンデンサの内部電極のような電子部品の微細な電極は、導電性のペーストを印刷によって塗布することによって形成されることが多い。このとき用いられるスクリーン印刷版には、微細な印刷パターンが形成されており、高い寸法精度と厚み精度が要求される。
【０００３】
微細な透過孔を有する第１の金属膜と、印刷パターン形状に相当する形状の印刷孔が形成された第２の金属膜とが金属メッキで一体形成されたスクリーン印刷版は、耐刷性に優れ、またメッキ量を制御することにより版の厚みを自由に設定できる。このようなスクリーン印刷版の製造には、エレクトロフォーミング技法が用いられる。
【０００４】
ところで、例えば積層セラミックコンデンサは、スクリーン印刷版を用いてセラミックグリーンシート上に内部電極となる導電性ペーストを印刷し、このグリーンシートを複数積層して焼成した後に、この積層体を切断することによって製造される。このとき、グリーンシート上には複数個のコンデンサの内部電極が一度に印刷される。そのため、スクリーン印刷版には同一形状の印刷孔が多数形成されている。
【０００５】
ここで、従来のスクリーン印刷版の平面図を図５（ａ）に、断面図を図５（ｂ）に示す。なお、図５（ｂ）ではグリーンシートなどの被印刷物と接触する面を上に、スキージと接触する面を下に図示しているが、通常は被印刷物と接触する面を下にして使用する。
【０００６】
スクリーン印刷版は２層の金属膜からなり、第１の金属膜３０にはペースト等を透過させるための透過孔５１が形成されており、第２の金属膜４０には印刷孔５２が形成されている。印刷孔５２は、例えば内部電極などの印刷パターンに相当する形状であり、透過孔５１は印刷孔５２に対応する部分に分布している。スクリーン印刷版の中央部付近は同形状の印刷孔５２が多数配置された印刷エリア６１となっており、スクリーン印刷版の辺縁付近は印刷孔５２のない辺縁部６２となっている。辺縁部６２には位置合わせ用などに用いられるマーカーを印刷するためのマーカー印刷孔５３などが形成されていることがある。
【０００７】
エレクトロフォーミング技法では、導電性の基材上に所定の形状に絶縁膜を形成した後、電解メッキを行い金属膜を得る。電解メッキによるメッキ析出速度は電流密度によって決まり、電流密度が大きいほど析出速度は増す。エレクトロフォーミング技法では絶縁性の絶縁膜を用いるため、絶縁膜で覆われた部分の周辺部では導電性の面の面積が小さくなって電流が集中し、電流密度が高くなる。よって、絶縁膜で覆われていた部分の周辺部ではメッキ膜が厚くなる。印刷エリア６１内には、印刷孔５２を形成するための絶縁膜が形成されているから、印刷エリア６１の中央部では電流密度が高くなってメッキ膜の膜厚が大きくなる。一方、印刷エリア６１内の周辺部分では、それ以上外側には絶縁膜が形成されないために電流密度が相対的に低くなり、印刷エリア６１の中心部よりも膜厚が薄くなってしまうのである。印刷エリア６１内の膜厚のばらつきは、印刷孔５２の形状によっても異なるが、印刷エリア６１内の中心部と印刷エリア６１内の周辺部とでは、最大で３０％程度になることもある。
【０００８】
スクリーン印刷版では、塗布物は図５（ｂ）の下方から透過孔５１を通って印刷孔５２内に供給され、印刷孔５２の内部に広がった塗布物が被印刷物に印刷される。そのため印刷パターンの形状は印刷孔５２の形状と略同一となり、印刷パターンの厚みは印刷孔５２の深さ、すなわち第２の金属膜４０の膜厚と略同一となる。よって、スクリーン印刷版の膜厚は印刷塗布厚を決定するうえで非常に重要であり、印刷エリア６１内の周辺部の膜厚が薄くなった印刷版を用いると、印刷塗布厚のばらつきが生じ、特に印刷エリア６１内の周辺部に配置された印刷孔５２では所定の印刷厚が得られないこととなる。
【０００９】
スクリーン印刷によって、積層セラミックコンデンサの内部電極などの電子部品の電極を印刷する場合、電極の厚みは部品の特性に影響を与えるため、印刷厚の精密な管理が必要とされる。所望の印刷厚が得られない場合には所望の特性を得ることができず不良が発生する。
【００１０】
この問題点を解決するための技術として、特許文献１に開示されている技術がある。この技術では、印刷エリア内の膜厚を均一にするために、印刷エリアの周囲にダミー図形を配置する。
【００１１】
【特許文献１】
特開平５−２３９６８２号公報
【特許文献２】
特開平５−３３８３７０号公報
【００１２】
【発明が解決しようとする課題】
上述した特許文献１の技術では、ダミー図形を広範な範囲に配置したほうが膜厚を均一化する効果が大きい。換言すれば、ダミー図形の配置領域が十分に広くない場合には膜圧の均一化が不十分となり、不良の発生を防ぐことができない。
【００１３】
ダミー図形が配置される領域は印刷エリアの周囲にある辺縁部であるが、上述したように辺縁部には位置合わせ用のマークを印刷するためのマーク印刷孔などが形成されていることがあり、このような場合にはダミー図形の配置には限りがある。
【００１４】
また、積層セラミックコンデンサなどの電子部品の製造コスト低減のため、一度の印刷でできるだけ多くの電極を印刷することが求められており、スクリーン印刷版全体に占める印刷エリアの面積の割合を大きくする必要がある。そのため、ダミー図形を十分に配置するほど辺縁部を広く確保することは難しいのが現状である。
【００１５】
そこで本発明は、印刷エリアを十分に広く確保しつつ印刷エリア内の膜厚を均一化したスクリーン印刷版およびその製造方法を提供することを目的とする。
【００１６】
ところで特許文献２では、開口部の縁辺に近接する溝を設けることにより、開口部が細幅の隔壁によって囲まれている発明が開示されている。この発明は形状が本発明と類似しているが、この技術は印刷版の裏面への塗布物の染み出し量を一定とするためのものであり、本発明とは作用効果が異なるものである。
【００１７】
【課題を解決するための手段】
上記問題点を解決するために本発明に係るスクリーン印刷版は、塗布物を通過させる透過孔を有する第１の金属膜と、印刷パターン形状に相当する形状の印刷孔が形成された第２の金属膜が一体化してなるスクリーン印刷版であって、第１の金属膜には、前記透過孔が印刷パターン形状に略対応して分布している透過部が複数箇所に形成され、第２の金属膜の少なくとも一部は、前記透過部のそれぞれを取り囲んで帯状に形成され、スクリーン印刷版の端部付近にある前記透過部を取り囲む前記帯状の第２の金属膜の幅は、スクリーン印刷版の中央部にある前記透過部を取り囲む前記帯状の第２の金属膜の幅よりも狭くなっていることを特徴とする。
【００１８】
これにより、透過部を取り囲む帯状の第２の金属膜の厚みが均一となり、印刷厚が均一となる。また、上記特許文献１に開示された技術のように印刷エリアの外側に多数のダミー図形を配置する必要がないから、スクリーン印刷版内に多くの印刷パターンを配置することができる。
【００１９】
あるいは、帯状の第２の金属膜の厚みをさらに均一にするために、帯状の第２の金属膜の幅を、スクリーン印刷版の端部に近いものほど狭くなるようにしてもよい。スクリーン印刷版の中央部付近から端部付近に向けて、帯状の第２の金属膜の幅が徐々に狭くなっていくように形成することによって、帯状の第２の金属膜の膜厚はさらに均一となる。
【００２０】
また、本発明に係るスクリーン印刷版の製造方法は、導電性の基材上に、透過孔に相当する形状の透過孔絶縁膜を印刷パターン形状に略対応するように分布させた透過孔絶縁膜部を複数箇所に形成する工程と、該透過孔絶縁膜が形成された部分を除いて、前記基材上に電解メッキによって第１の金属膜を形成する工程と、前記透過孔絶縁膜を除去する工程と、前記第１の金属膜上に、印刷パターン形状に相当する形状の複数の印刷孔絶縁膜と、該印刷孔絶縁膜から所定の間隔を置いてこれを取り囲み、前記第１の金属膜の中央部付近における前記間隔よりも前記第１の金属膜の端部付近における前記間隔のほうが狭くなるように、ダミー絶縁膜を形成する工程と、前記印刷孔絶縁膜と前記ダミー絶縁膜が形成された領域を除いて、前記第１の金属膜上に電解メッキによって第２の金属膜を形成する工程と、前記印刷孔絶縁膜および前記ダミー絶縁膜を除去する工程とを含むことを特徴とする。あるいは、第２の金属膜を形成する前に透過孔絶縁膜を除去するのではなく、第２の金属膜を形成した後に印刷孔絶縁膜、ダミー絶縁膜とともに透過孔絶縁膜を除去する方法であってもよい。
【００２１】
これにより、帯状の第２の金属膜が析出する部分における電流密度の均一化が可能となり、結果として帯状の第２の金属膜の膜厚が均一化される。
【００２２】
また、該印刷孔絶縁膜から所定の間隔を置いてこれを取り囲み、前記間隔は前記第１の金属膜の端部に近いほど狭くなるように、ダミー絶縁膜を形成してもよい。
【００２３】
これにより、帯状の第２の金属膜が析出する部分の電流密度はさらに均一となり、結果として帯状の第２の金属膜の膜厚はさらに均一なものとなる。
【００２４】
【発明の実施の形態】
（第１の実施例）以下に図を参照しつつ、本発明の一実施形態を説明する。図１を参照して本発明の製造方法について詳細に説明する。なお、図１においては図の右方向がスクリーン印刷版の中央方向であり、図の左方向がスクリーン印刷版の端部方向である。
【００２５】
まず、導電性の基材１０、例えばステンレスの基材１０を用意し、図１（ａ）に示すように、フォトリソグラフィなどの方法により、基材１０上に電気絶縁性の透過孔絶縁膜２１を形成する。透過孔絶縁膜２１は印刷パターン形状に略対応して複数箇所に分かれて分布している。透過孔絶縁膜２１が分布するそれぞれの部分を透過孔絶縁膜部２３とする。透過孔絶縁膜部２３は印刷エリア６１内の複数箇所に設けられる。
【００２６】
次に、図１（ｂ）に示すように、透過孔絶縁膜２１が形成された領域を除いて、１回目の電解メッキにより例えばニッケルからなる第１の金属膜３０が形成される。特許文献１に記載された技術においては、この第１の金属膜３０の膜厚を均一にするためにダミー絶縁膜が形成されている。しかし、透過孔は微細であり、これに相当する形状の透過孔絶縁膜２１は面積が小さいため、第１の金属膜３０の膜厚を３０μｍ以下にした場合には、透過孔絶縁膜２１の影響による電流密度の変化は膜厚にほとんど影響を与えないことが本発明者らの研究によって見出された。よって、ダミー絶縁膜を形成しなくとも第１の金属膜３０は均一な厚みで形成される。
【００２７】
次に、図１（ｃ）に示すように透過孔絶縁膜２１を溶解剥離し、図１（ｄ）に示すように、第１の金属膜３０上に、印刷パターンに相当する形状の印刷孔絶縁膜２２とダミー絶縁膜２４とを形成する。
【００２８】
ここでは、ダミー絶縁膜２４は特許文献１に記載された技術のように印刷エリア６１の外側に配置されるのではなく、印刷エリア６１内に印刷孔絶縁膜２２の一つ一つを取り囲んで形成される。このダミー絶縁膜２４は、後に説明する隔壁が均一な厚みをもって形成されるようにするためのものである。印刷エリア６１内の最外周に位置する印刷孔絶縁膜２２の付近では、印刷孔絶縁膜２２とダミー絶縁膜２４との間隔を狭くして電流が集中しやすくする。すなわち、印刷エリア６１の中央部付近（図１の右側）では周囲に多くの印刷孔絶縁膜２２が形成されるため、電流密度が比較的大きくなるのに対し、印刷エリア６１内の外周部分に配置される印刷孔絶縁膜２２付近では、それ以上外側に印刷孔絶縁膜２２が形成されないため、電流密度が比較的小さくなりやすい。電解メッキでは、メッキ皮膜の析出速度は電流密度に比例するため、電流密度が小さくなると単位時間あたりに析出するメッキ皮膜の厚みが薄くなってしまう。そこで、印刷エリア６１の中心部付近では印刷孔絶縁膜２２とダミー絶縁膜２４との距離を比較的大きくし、印刷エリア６１内の外周部では印刷孔絶縁膜２２とダミー絶縁膜２４との距離を比較的小さくすることにより、印刷エリア６１の外周に位置する印刷孔絶縁膜２２付近でも電流密度が上がりやすくし、印刷エリア６１内での電流密度が均一になるようにすることができる。
【００２９】
次に、図１（ｄ）に示すように、印刷孔絶縁膜２２あるいはダミー絶縁膜２４が形成された部分を除き、２回目の電解メッキによって第２の金属膜４０を形成する。第２の金属膜４０のうち、印刷孔絶縁膜２２とダミー絶縁膜２４との間にある溝部分に形成される帯状の金属膜４１を、言い換えれば印刷孔絶縁膜２２の周囲を取り囲む金属膜４１を以下においては「隔壁４１」と称する。
【００３０】
印刷エリア６１内の最外周に位置する印刷孔絶縁膜２２の周囲を取り囲む隔壁４１はその他の部分の隔壁４１よりも幅が狭く形成されている。ダミー絶縁膜２４の効果によって印刷エリア６１内の電流密度はほぼ均一になるため、隔壁４１は均一な厚みで形成される。また、隔壁４１の内周は印刷パターンの形状に相当する形状となる。
【００３１】
本実施例では、印刷エリア６１全体を取り囲むように、隔壁以外の第２の金属膜４２が形成されているが、この部分はなくてもよい。また、隔壁以外の第２の金属膜４２では膜厚が低下している部分があるが、この部分は印刷パターンの印刷には関与しない部分であるから、膜厚が薄くなっていても問題はない。
【００３２】
上述したように１回目の電解メッキの際に形成される透過孔絶縁膜２１は透過孔の形状に相当する形状であって面積が小さいために電流の集中する度合いが小さいから、ダミー絶縁膜を形成しなくても膜厚は一定に保たれる。しかし、２回目の電解メッキの際には、形成されている印刷孔絶縁膜２２は印刷パターンの形状に相当しており透過孔絶縁膜２１よりも面積が大きいから、電流の集中する度合いが高く、本発明者が実験したところによれば、膜厚が８μｍ以上になるとダミー絶縁膜２４なしでは印刷エリア６１内の隔壁４１の膜厚を均一に形成できない。よって、ダミー絶縁膜２４を形成しない場合、印刷エリア６１内での膜厚のばらつきは、最大で膜厚の３０％程度になることもあるが、ダミー絶縁膜２４を配置することにより、印刷エリア６１内での膜厚のばらつきを膜厚の１０％未満に抑えることができる。なお、第２の金属膜４０の膜厚は、印刷物の用途等によって異なるが、８μｍから３０μｍ程度であり、第２の金属膜４０の膜厚が８μｍ以上である場合には、ダミー絶縁膜２４を形成しなければ印刷エリア６１内の膜厚を均一に保つことができない。
【００３３】
次に、印刷孔絶縁膜２２およびダミー絶縁膜２４を除去し、一体となって形成された第１および第２の金属膜３０，４０を基材から剥離して、図１（ｆ）に示すようなスクリーン印刷版が得られる。このスクリーン印刷版の平面図を図２（ａ）に、図２（ａ）におけるＡ−Ａ線断面図を図２（ｂ）に示す。印刷孔５２を取り囲む帯状の隔壁４１の幅は、最外周で他よりも狭くなっている。
【００３４】
図３は、このスクリーン印刷版の斜視図を示している。印刷パターン形状に略対応して透過孔５１が分布している領域（図１（ｆ）に示した透過部５４）を取り囲むようにして帯状の隔壁４１が形成されている。隔壁４１によって取り囲まれた領域が印刷孔５２であり、図の下方から透過孔５１を通過してきたペーストが印刷孔５２の内部に広がって印刷図形の形状となり、被印刷物に所望の図形を印刷することができる。
【００３５】
図３および図２（ａ）にあるように、印刷エリア６１の外側には位置合わせなどに利用されるマーカーを印刷するためのマーカー印刷孔５３が必要に応じて設けられていることがある。本発明では、ダミー絶縁膜２４を印刷エリア６１内に形成することから、マーカー印刷孔５３を設けるための領域を印刷エリア６１の外側に十分に確保することができ、また、ダミー絶縁膜２４を印刷エリア６１の外側に設ける場合と比較して辺縁部６２の幅を狭くすることができるから、印刷エリア６１の面積を従来よりも広くとることができて生産性が向上する。
【００３６】
なお、マーカー印刷孔部分では膜厚が均一でないが、マーカーは電子部品の電極などとして使用されるものではないので、マーカーの印刷厚を均一にする必要はないから、この部分での膜厚のばらつきは実用上何ら問題ない。
【００３７】
本実施例においては、透過孔絶縁膜を剥離したのちに印刷孔絶縁膜およびダミー絶縁膜を形成したが、透過孔絶縁膜を剥離せずに印刷孔絶縁膜およびダミー絶縁膜を形成し、第２の金属膜を形成してから、印刷孔絶縁膜およびダミー絶縁膜と同時に透過孔絶縁膜を剥離してもよい。
【００３８】
（第２の実施例）図４（ａ）は本発明の第２の実施例に係るスクリーン印刷版の平面図であり、図４（ｂ）はその断面図である。このスクリーン印刷版の製造工程は上記第１の実施例と同様であるが、上記第１の実施例においては透過部５４を取り囲む隔壁４１の幅は最外周に配置されたものにおいて他よりも狭く設定されていたが、本実施例においては、印刷エリア６０の中央部から周辺部に向かうにつれて隔壁４１の幅が徐々に狭くなるように設定されている。すなわちＤ１＞Ｄ２＞Ｄ３となっている。
【００３９】
エレクトロフォーミング技法でスクリーン印刷版を形成すると印刷エリア６１の中心がもっとも電流が集中しやすく、中央から周辺に向かうにつれて徐々に電流密度が低下していく傾向にあるから、印刷エリア６１の中央から周辺部に向かうにつれて隔壁４１の幅が徐々に狭くなるように設定することにより、印刷エリア６１内での電流密度をより均一にすることができ、印刷エリア６１内の第２の金属膜４０の膜厚をより均一にすることができる。
【００４０】
上記第１および第２の実施例では、透過孔５１は略正方形状に図示されているが、透過孔５１の形状がこれに限られるものではないことは言うまでもなく、例えば略円形であってもよいし、スリット状であってもよい。
【００４１】
【発明の効果】
本発明は、以上説明したように構成されるもので、以下に記載するような効果を奏するものである。
【００４２】
すなわち、印刷孔絶縁膜とダミー絶縁膜の間隔がスクリーン印刷版の端部において中央部よりも狭くなるように、あるいは中央部から端部に向けて徐々に狭くなっていくようにすることにより、言いかえれば帯状の第２の金属膜（隔壁）の幅がスクリーン印刷版の端部において中央部よりも狭くなるように、あるいは中央部から端部に向けて徐々に狭くなっていくようにすることにより、帯状の第２の金属膜（隔壁）が析出する部分の電流密度が均一化されて、帯状の第２の金属膜（隔壁）が均一な厚みで形成されることとなる。この結果、スクリーン印刷版で一度に印刷される複数の印刷パターンを均一な印刷厚で印刷することができる。
【図面の簡単な説明】
【図１】本発明の第１の実施例に係るスクリーン印刷版の製造工程を示す断面図である。
【図２】本発明の第１の実施例に係るスクリーン印刷版の平面図および断面図である。
【図３】本発明の第１の実施例に係るスクリーン印刷版の斜視図である。
【図４】本発明の第２の実施例に係るスクリーン印刷版の平面図および断面図である。
【図５】従来のスクリーン印刷版を示す平面図および断面図である。
【符号の説明】
１０基材
２１透過孔絶縁膜
２２印刷孔絶縁膜
２３透過孔絶縁膜部
２４ダミー絶縁膜
３０第１の金属膜
４０第２の金属膜
４１隔壁
４２隔壁以外の第２の金属膜
５１透過孔
５２印刷孔
５３マーカー孔
５４透過部
６１印刷エリア
６２辺縁部[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a screen printing plate used for screen printing and a method for manufacturing the same, and more particularly, to uniforming the thickness of the screen printing plate when producing the screen printing plate by an electroforming technique.
[0002]
[Prior art]
Fine electrodes of electronic components such as internal electrodes of multilayer ceramic capacitors are often formed by applying a conductive paste by printing. A fine printing pattern is formed on the screen printing plate used at this time, and high dimensional accuracy and thickness accuracy are required.
[0003]
A screen printing plate in which a first metal film having fine transmission holes and a second metal film having a printing hole having a shape corresponding to the shape of a printing pattern are integrally formed by metal plating has a high printing durability. Excellent, and the thickness of the plate can be freely set by controlling the plating amount. Electroforming techniques are used to produce such screen printing plates.
[0004]
By the way, for example, a multilayer ceramic capacitor is obtained by printing a conductive paste to be an internal electrode on a ceramic green sheet using a screen printing plate, laminating a plurality of the green sheets, firing the green sheets, and cutting the laminate. Manufactured. At this time, the internal electrodes of a plurality of capacitors are printed on the green sheet at a time. Therefore, a large number of printing holes of the same shape are formed in the screen printing plate.
[0005]
Here, FIG. 5A shows a plan view of a conventional screen printing plate, and FIG. 5B shows a cross-sectional view thereof. In FIG. 5B, the surface that comes into contact with the printing material such as a green sheet is shown above, and the surface that comes into contact with the squeegee is shown below. .
[0006]
The screen printing plate is composed of two layers of metal films. The first metal film 30 has a transmission hole 51 for transmitting a paste or the like, and the second metal film 40 has a printing hole 52. ing. The printing holes 52 have a shape corresponding to a printing pattern of, for example, an internal electrode, and the transmission holes 51 are distributed in portions corresponding to the printing holes 52. The vicinity of the center of the screen printing plate is a printing area 61 in which a large number of printing holes 52 of the same shape are arranged, and the vicinity of the periphery of the screen printing plate is a periphery 62 having no printing holes 52. A marker printing hole 53 for printing a marker used for positioning or the like may be formed in the peripheral portion 62 in some cases.
[0007]
In the electroforming technique, after forming an insulating film in a predetermined shape on a conductive base material, electrolytic plating is performed to obtain a metal film. The plating deposition rate by electrolytic plating is determined by the current density, and the deposition rate increases as the current density increases. Since an insulating insulating film is used in the electroforming technique, the area of the conductive surface is reduced around the portion covered with the insulating film, current is concentrated, and the current density is increased. Therefore, the plating film becomes thicker in the peripheral portion of the portion covered with the insulating film. Since an insulating film for forming the printing hole 52 is formed in the printing area 61, the current density increases in the center of the printing area 61, and the thickness of the plating film increases. On the other hand, in the peripheral portion in the printing area 61, the current density is relatively low because the insulating film is not formed further outside, so that the film thickness is smaller than the central portion of the printing area 61. The variation in the film thickness in the printing area 61 varies depending on the shape of the printing hole 52, but may be up to about 30% between the central part in the printing area 61 and the peripheral part in the printing area 61.
[0008]
In the screen printing plate, the coating material is supplied from below in FIG. 5B into the printing hole 52 through the transmission hole 51, and the coating material spread inside the printing hole 52 is printed on the printing material. Therefore, the shape of the printing pattern is substantially the same as the shape of the printing hole 52, and the thickness of the printing pattern is substantially the same as the depth of the printing hole 52, that is, the thickness of the second metal film 40. Therefore, the thickness of the screen printing plate is very important in determining the printing coating thickness, and when a printing plate having a thinner peripheral portion in the printing area 61 is used, the printing coating thickness varies. In particular, a predetermined printing thickness cannot be obtained in the printing holes 52 arranged at the peripheral portion in the printing area 61.
[0009]
When printing electrodes of an electronic component such as an internal electrode of a multilayer ceramic capacitor by screen printing, the thickness of the electrode affects the characteristics of the component, so that precise control of the printed thickness is required. If the desired printing thickness cannot be obtained, the desired characteristics cannot be obtained and a defect occurs.
[0010]
As a technique for solving this problem, there is a technique disclosed in Patent Document 1. In this technique, dummy figures are arranged around the print area in order to make the film thickness in the print area uniform.
[0011]
[Patent Document 1]
JP-A-5-239682 [Patent Document 2]
JP-A-5-338370
[Problems to be solved by the invention]
In the technique of Patent Document 1 described above, arranging dummy figures in a wider range has a greater effect of making the film thickness uniform. In other words, when the arrangement area of the dummy figure is not sufficiently large, the film thickness is not sufficiently uniformized, and the occurrence of defects cannot be prevented.
[0013]
The area where the dummy figure is arranged is an edge around the printing area, but a mark printing hole or the like for printing a positioning mark is formed in the edge as described above. In such a case, the arrangement of the dummy figures is limited.
[0014]
Also, in order to reduce the manufacturing cost of electronic components such as multilayer ceramic capacitors, it is required to print as many electrodes as possible in one printing, and it is necessary to increase the proportion of the printing area in the entire screen printing plate. There is. For this reason, it is difficult at present to secure a wide marginal portion so that the dummy figures are sufficiently arranged.
[0015]
Therefore, an object of the present invention is to provide a screen printing plate in which the film area in the printing area is made uniform while securing a sufficiently large printing area, and a method of manufacturing the screen printing plate.
[0016]
Meanwhile, Patent Literature 2 discloses an invention in which a groove is provided near an edge of an opening so that the opening is surrounded by a narrow-width partition wall. Although the present invention is similar in shape to the present invention, this technique is intended to keep the amount of the applied material oozing to the back surface of the printing plate constant, and has different functions and effects from the present invention. .
[0017]
[Means for Solving the Problems]
In order to solve the above problems, a screen printing plate according to the present invention has a first metal film having a transmission hole through which a coating material passes, and a second metal film having a printing hole having a shape corresponding to a printing pattern shape. A screen printing plate in which a metal film is integrated, wherein the first metal film has a plurality of transmission portions in which the transmission holes are distributed substantially corresponding to a print pattern shape. At least a part of the metal film is formed in a band shape surrounding each of the transmission portions, and the width of the band-shaped second metal film surrounding the transmission portion near the end of the screen printing plate is a screen printing plate. The width is smaller than the width of the band-shaped second metal film surrounding the transmitting portion at the center of the second metal film.
[0018]
Thereby, the thickness of the band-shaped second metal film surrounding the transmission portion becomes uniform, and the printing thickness becomes uniform. Further, since there is no need to arrange a large number of dummy figures outside the print area as in the technique disclosed in Patent Document 1, it is possible to arrange many print patterns in the screen printing plate.
[0019]
Alternatively, in order to make the thickness of the band-shaped second metal film even more uniform, the width of the band-shaped second metal film may be made narrower nearer the edge of the screen printing plate. By forming the band-shaped second metal film such that the width of the band-shaped second metal film gradually decreases from the vicinity of the center portion to the vicinity of the end portion of the screen printing plate, the thickness of the band-shaped second metal film further increases. Become uniform.
[0020]
In addition, the method of manufacturing a screen printing plate according to the present invention is a method of manufacturing a screen printing plate, wherein a transmission hole insulating film having a shape corresponding to a transmission hole is distributed on a conductive base material so as to substantially correspond to a print pattern shape. Forming a portion at a plurality of locations, forming a first metal film on the substrate by electrolytic plating except for the portion where the through-hole insulating film is formed, and removing the through-hole insulating film. Forming a plurality of printing hole insulating films having a shape corresponding to a printing pattern shape on the first metal film, surrounding the printing hole insulating film at a predetermined distance from the printing hole insulating film, Forming a dummy insulating film such that the distance in the vicinity of the end of the first metal film is smaller than the distance in the vicinity of the center of the film; Except for the formed area, the first Forming a second metal film by electroplating on Shokumaku, characterized in that it comprises a step of removing the print hole insulating film and the dummy insulating film. Alternatively, instead of removing the through hole insulating film before forming the second metal film, a method of removing the through hole insulating film together with the printed hole insulating film and the dummy insulating film after forming the second metal film. There may be.
[0021]
Thereby, the current density can be made uniform in the portion where the band-shaped second metal film is deposited, and as a result, the film thickness of the band-shaped second metal film is made uniform.
[0022]
Also, a dummy insulating film may be formed so as to surround the printing hole insulating film at a predetermined distance from the insulating film, and to narrow the space closer to an end of the first metal film.
[0023]
Accordingly, the current density in the portion where the band-shaped second metal film is deposited becomes more uniform, and as a result, the film thickness of the band-shaped second metal film becomes more uniform.
[0024]
BEST MODE FOR CARRYING OUT THE INVENTION
(First Embodiment) An embodiment of the present invention will be described below with reference to the drawings. The manufacturing method of the present invention will be described in detail with reference to FIG. In FIG. 1, the right direction in the figure is the center direction of the screen printing plate, and the left direction in the figure is the end direction of the screen printing plate.
[0025]
First, a conductive base material 10, for example, a stainless steel base material 10 is prepared, and as shown in FIG. 1A, an electrically insulating through-hole insulating film 21 is formed on the base material 10 by a method such as photolithography. To form The through-hole insulating film 21 is distributed at a plurality of locations substantially corresponding to the print pattern shape. Each part where the transmission hole insulating film 21 is distributed is referred to as a transmission hole insulating film portion 23. The through-hole insulating film portion 23 is provided at a plurality of locations in the printing area 61.
[0026]
Next, as shown in FIG. 1B, a first metal film 30 made of, for example, nickel is formed by the first electrolytic plating except for a region where the transmission hole insulating film 21 is formed. In the technique described in Patent Document 1, a dummy insulating film is formed to make the thickness of the first metal film 30 uniform. However, the through-holes are fine, and the through-hole insulating film 21 having a shape corresponding to this is small in area. Therefore, when the thickness of the first metal film 30 is set to 30 μm or less, the thickness of the through-hole insulating film 21 is reduced. It has been found by the present inventors that the change in current density due to the influence hardly affects the film thickness. Therefore, the first metal film 30 is formed with a uniform thickness without forming a dummy insulating film.
[0027]
Next, as shown in FIG. 1C, the through-hole insulating film 21 is dissolved and peeled off, and as shown in FIG. 1D, a printed hole having a shape corresponding to a print pattern is formed on the first metal film 30. An insulating film 22 and a dummy insulating film 24 are formed.
[0028]
Here, the dummy insulating film 24 is not disposed outside the printing area 61 as in the technology described in Patent Document 1, but surrounds each of the printing hole insulating films 22 in the printing area 61. It is formed. This dummy insulating film 24 is for ensuring that a partition wall described later is formed with a uniform thickness. In the vicinity of the printing hole insulating film 22 located at the outermost periphery in the printing area 61, the gap between the printing hole insulating film 22 and the dummy insulating film 24 is narrowed so that the current is easily concentrated. That is, in the vicinity of the center of the print area 61 (right side in FIG. 1), a large number of print hole insulating films 22 are formed around the print area 61, so that the current density becomes relatively large. In the vicinity of the printed hole insulating film 22 to be arranged, the printed hole insulating film 22 is not formed further outside, so that the current density tends to be relatively small. In electrolytic plating, the deposition rate of a plating film is proportional to the current density. Therefore, when the current density is low, the thickness of the plating film deposited per unit time becomes thin. Therefore, the distance between the printing hole insulating film 22 and the dummy insulating film 24 is relatively large near the center of the printing area 61, and the distance between the printing hole insulating film 22 and the dummy insulating film 24 is relatively large in the outer peripheral portion of the printing area 61. Is relatively small, the current density can be easily increased even in the vicinity of the printing hole insulating film 22 located on the outer periphery of the printing area 61, and the current density in the printing area 61 can be made uniform.
[0029]
Next, as shown in FIG. 1D, a second metal film 40 is formed by a second electrolytic plating except for a portion where the printed hole insulating film 22 or the dummy insulating film 24 is formed. The band-shaped metal film 41 formed in the groove portion between the printing hole insulating film 22 and the dummy insulating film 24 in the second metal film 40, in other words, the metal film surrounding the periphery of the printing hole insulating film 22. Hereinafter, 41 will be referred to as “partition wall 41”.
[0030]
The partition wall 41 surrounding the periphery of the print hole insulating film 22 located at the outermost periphery in the print area 61 is formed to be narrower than the other partition walls 41. Since the current density in the print area 61 becomes substantially uniform due to the effect of the dummy insulating film 24, the partition wall 41 is formed with a uniform thickness. The inner periphery of the partition 41 has a shape corresponding to the shape of the print pattern.
[0031]
In the present embodiment, the second metal film 42 other than the partition wall is formed so as to surround the entire printing area 61, but this portion may be omitted. In the second metal film 42 other than the partition walls, there is a portion where the film thickness is reduced. However, since this portion is not involved in the printing of the print pattern, there is no problem even if the film thickness is reduced. Absent.
[0032]
As described above, the through-hole insulating film 21 formed at the time of the first electrolytic plating has a shape corresponding to the shape of the through-hole and a small area, so that the degree of current concentration is small. Even without forming, the film thickness is kept constant. However, at the time of the second electrolytic plating, since the formed printed hole insulating film 22 corresponds to the shape of the printed pattern and has a larger area than the transmitted hole insulating film 21, the degree of current concentration is high. According to an experiment conducted by the inventor, when the film thickness is 8 μm or more, the thickness of the partition wall 41 in the print area 61 cannot be formed uniformly without the dummy insulating film 24. Therefore, when the dummy insulating film 24 is not formed, the variation of the film thickness in the print area 61 may be about 30% of the film thickness at the maximum. Variations in film thickness within 61 can be suppressed to less than 10% of the film thickness. The thickness of the second metal film 40 is about 8 μm to 30 μm although it varies depending on the use of the printed material and the like. When the thickness of the second metal film 40 is 8 μm or more, the dummy insulating film 24 is formed. Unless the film thickness is formed, the film thickness in the printing area 61 cannot be kept uniform.
[0033]
Next, the printed hole insulating film 22 and the dummy insulating film 24 are removed, and the integrally formed first and second metal films 30 and 40 are peeled off from the base material, as shown in FIG. Such a screen printing plate is obtained. FIG. 2A is a plan view of the screen printing plate, and FIG. 2B is a cross-sectional view taken along line AA in FIG. The width of the strip-shaped partition wall 41 surrounding the printing hole 52 is narrower at the outermost periphery than the others.
[0034]
FIG. 3 shows a perspective view of the screen printing plate. A strip-shaped partition wall 41 is formed so as to surround a region where the transmission holes 51 are distributed substantially corresponding to the print pattern shape (the transmission portion 54 shown in FIG. 1F). The area surrounded by the partition wall 41 is the printing hole 52, and the paste that has passed through the transmission hole 51 from below in the figure spreads inside the printing hole 52 to form a printed figure, and prints a desired figure on a printing substrate. be able to.
[0035]
As shown in FIGS. 3 and 2A, a marker printing hole 53 for printing a marker used for alignment or the like may be provided outside the printing area 61 as necessary. In the present invention, since the dummy insulating film 24 is formed in the printing area 61, a region for providing the marker printing hole 53 can be sufficiently secured outside the printing area 61. Since the width of the peripheral portion 62 can be reduced as compared with the case where it is provided outside the printing area 61, the area of the printing area 61 can be made larger than before, and the productivity is improved.
[0036]
In addition, although the film thickness is not uniform in the marker printing hole portion, since the marker is not used as an electrode of an electronic component, it is not necessary to make the marker printing thickness uniform. The variation is practically no problem.
[0037]
In the present embodiment, the printing hole insulating film and the dummy insulating film were formed after the through hole insulating film was peeled off, but the printing hole insulating film and the dummy insulating film were formed without peeling the through hole insulating film. After forming the second metal film, the through hole insulating film may be peeled off simultaneously with the printing hole insulating film and the dummy insulating film.
[0038]
Second Embodiment FIG. 4A is a plan view of a screen printing plate according to a second embodiment of the present invention, and FIG. 4B is a sectional view thereof. The manufacturing process of the screen printing plate is the same as that of the first embodiment. However, in the first embodiment, the width of the partition wall 41 surrounding the transmission portion 54 is smaller than that of the other one disposed at the outermost periphery. Although set in this embodiment, the width of the partition 41 is set so as to gradually decrease from the center of the print area 60 toward the periphery. That is, D1>D2> D3.
[0039]
When a screen printing plate is formed by an electroforming technique, the current tends to concentrate most at the center of the printing area 61, and the current density tends to gradually decrease from the center to the periphery. The current density in the printing area 61 can be made more uniform by setting the width of the partition wall 41 to gradually decrease toward the portion, and the film thickness of the second metal film 40 in the printing area 61 is reduced. The thickness can be made more uniform.
[0040]
In the first and second embodiments, the transmission hole 51 is illustrated in a substantially square shape, but it is needless to say that the shape of the transmission hole 51 is not limited to this. Or a slit shape.
[0041]
【The invention's effect】
The present invention is configured as described above, and has the following effects.
[0042]
That is, by making the interval between the printing hole insulating film and the dummy insulating film narrower than the center at the end of the screen printing plate, or by gradually narrowing from the center to the end, In other words, the width of the band-shaped second metal film (partition wall) is made smaller at the end of the screen printing plate than at the center, or gradually narrowed from the center to the end. Accordingly, the current density in the portion where the band-shaped second metal film (partition) is deposited is made uniform, and the band-shaped second metal film (partition) is formed with a uniform thickness. As a result, it is possible to print a plurality of print patterns that are printed at once on the screen printing plate with a uniform print thickness.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating a manufacturing process of a screen printing plate according to a first embodiment of the present invention.
FIG. 2 is a plan view and a sectional view of a screen printing plate according to a first embodiment of the present invention.
FIG. 3 is a perspective view of the screen printing plate according to the first embodiment of the present invention.
FIG. 4 is a plan view and a sectional view of a screen printing plate according to a second embodiment of the present invention.
FIG. 5 is a plan view and a sectional view showing a conventional screen printing plate.
[Explanation of symbols]
Reference Signs List 10 base material 21 transmission hole insulating film 22 printing hole insulating film 23 transmission hole insulating film part 24 dummy insulating film 30 first metal film 40 second metal film 41 partition 42 second metal film 51 other than partition 51 transmission hole 52 Printing hole 53 Marker hole 54 Transmission part 61 Printing area 62 Edge

Claims

A screen printing plate in which a first metal film having a transmission hole through which a coating material passes and a second metal film in which a printing hole having a shape corresponding to a printing pattern shape is formed,
In the first metal film, a plurality of transmission portions in which the transmission holes are distributed substantially corresponding to the print pattern shape are formed,
At least a portion of the second metal film is formed in a band shape surrounding each of the transmission portions,
The width of the band-shaped second metal film surrounding the transmission portion near the end of the screen printing plate is greater than the width of the band-shaped second metal film surrounding the transmission portion at the center of the screen printing plate. Screen printing plate characterized in that it is also narrow.

A screen printing plate in which a first metal film having a transmission hole through which a coating material passes and a second metal film in which a printing hole having a shape corresponding to a printing pattern shape is formed,
In the first metal film, a plurality of transmission portions in which the transmission holes are distributed substantially corresponding to the print pattern shape are formed,
At least a portion of the second metal film is formed in a band shape surrounding each of the transmission portions,
The width of the band-shaped second metal film becomes narrower nearer the edge of the screen printing plate.

A step of forming a plurality of transmission hole insulating film portions in which a transmission hole insulating film having a shape corresponding to a transmission hole is distributed on the conductive substrate so as to substantially correspond to the print pattern shape,
Forming a first metal film on the base material by electrolytic plating except for a portion where the through-hole insulating film is formed;
Removing the through-hole insulating film;
A plurality of printing hole insulating films having a shape corresponding to a printing pattern shape, and surrounding the first metal film at a predetermined distance from the printing hole insulating film, and a central portion of the first metal film; Forming a dummy insulating film such that the distance in the vicinity of the end of the first metal film is smaller than the distance in the vicinity thereof;
Forming a second metal film by electrolytic plating on the first metal film except for a region where the printing hole insulating film and the dummy insulating film are formed;
Removing the printing hole insulating film and the dummy insulating film.

A step of forming a plurality of transmission hole insulating film portions in which a transmission hole insulating film having a shape corresponding to a transmission hole is distributed on the conductive substrate so as to substantially correspond to the print pattern shape,
Forming a first metal film on the base material by electrolytic plating except for a portion where the through-hole insulating film is formed;
On the first metal film and the transmission hole insulating film, a plurality of printing hole insulating films having a shape corresponding to a printing pattern shape, and surrounding the printing hole insulating film at a predetermined distance from the printing hole insulating film, Forming a dummy insulating film such that the distance near the end of the first metal film is smaller than the distance near the center of the metal film.
Forming a second metal film by electrolytic plating on the first metal film except for a region where the printing hole insulating film and the dummy insulating film are formed;
Removing the transmission hole insulating film, the printing hole insulating film, and the dummy insulating film.

A step of forming a plurality of transmission hole insulating film portions in which a transmission hole insulating film having a shape corresponding to the transmission hole is distributed on the conductive base material so as to substantially correspond to the print pattern shape,
Forming a first metal film on the base material by electrolytic plating except for a portion where the through-hole insulating film is formed;
Removing the through-hole insulating film;
On the first metal film, a plurality of printing hole insulating films having a shape corresponding to a printing pattern shape, and surrounding the printing hole insulating film at a predetermined interval from the printing hole insulating film, wherein the interval is the first metal film. Forming a dummy insulating film so as to be narrower as it is closer to the end of
Forming a second metal film by electrolytic plating on the first metal film except for a region where the printing hole insulating film and the dummy insulating film are formed;
Removing the printing hole insulating film and the dummy insulating film.

A step of forming a plurality of transmission hole insulating film portions in which a transmission hole insulating film having a shape corresponding to the transmission hole is distributed on the conductive base material so as to substantially correspond to the print pattern shape,
Forming a first metal film on the base material by electrolytic plating except for a portion where the through-hole insulating film is formed;
On the first metal film and the transmission hole insulating film, a printing hole insulating film having a shape corresponding to a printing pattern shape, and surrounding the printing hole insulating film at a predetermined distance from the printing hole insulating film,
Forming a dummy insulating film such that the distance becomes narrower nearer to the end of the first metal film;
Forming a second metal film by electrolytic plating on the first metal film except for a region where the printing hole insulating film and the dummy insulating film are formed;
Removing the printing hole insulating film and the dummy insulating film.