JP2004017461A

JP2004017461A - Screen printing plate

Info

Publication number: JP2004017461A
Application number: JP2002175012A
Authority: JP
Inventors: Akifumi Fujita; 藤田　彰文; Yutaka Izeki; 井関　裕
Original assignee: Murata Manufacturing Co Ltd
Current assignee: Murata Manufacturing Co Ltd
Priority date: 2002-06-14
Filing date: 2002-06-14
Publication date: 2004-01-22
Anticipated expiration: 2022-06-14
Also published as: JP3966092B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a screen printing plate which can obtain a uniform printing pattern area and a uniform application thickness over the entire printing region. <P>SOLUTION: In the structure of a screen printing mask 1, a mesh part 16 and a figure part 17 are arranged in the thickness direction. In the mesh part 16, a plurality of rectangular holes 16a arranged two-dimensionally and regularly in the shape of a lattice are formed. In the figure part 17, a plurality of rectangular recessed parts 17a having a plane shape corresponding to the printing pattern in which the same figures are arranged in a prescribed pitch are formed. The numerical aperture of the mesh part 16 arranged in the peripheral part 4a of the printing region 4 is set up to be larger than the standard numerical aperture of the mesh part 16 arranged in the inside part 4b surrounded by the peripheral part 4a. The numerical aperture of the mesh part 16 arranged in the peripheral part 4a is increased by enlarging the diameter of the holes 16a and increasing the number of the holes 16a. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、スクリーン印刷版、例えば、電子部品の内部電極をセラミックグリーンシートに印刷するときに用いるスクリーン印刷版に関する。
【０００２】
【従来の技術】
従来より、電子部品の内部電極をマザーセラミックグリーンシートに印刷するときに用いるスクリーン印刷版として、例えば図７に示すものが知られている。図７はスクリーン印刷版５１を下面側から見た図である。このスクリーン印刷版５１は、額縁状の枠部材５２の下面にスクリーン印刷マスク５３が装着されている。スクリーン印刷マスク５３の中央部分を囲む一点鎖線５４は、印刷対象の被印刷物（マザーセラミックグリーンシート）に応じて設定される印刷領域である。印刷領域５４には、被印刷物上の所望の位置に導電性ペーストを塗布して印刷パターンを形成するための多数の開口部５６が形成されている。それぞれの開口部５６の形状は同一である。なお、図７において、開口部５６はその一部しか表示されていない。
【０００３】
以上の構成からなるスクリーン印刷版５１は、その下面をスクリーン印刷装置の印刷テーブルの上面から所定の隙間寸法だけ離隔させた状態で、すなわちオフコンタクト状態でセットされる。スクリーン印刷マスク５３の上面にはスキージが配置される。スクリーン印刷においては、スクリーン印刷マスク５３上に供給された導電性のペーストをスキージによって掻き寄せ、所定の方向に掃引してスクリーン印刷マスク５３の開口部５６内に押し込むことによって、印刷テーブルに載せられた被印刷物上の所望の位置に導電性ペーストが塗布される。
【０００４】
【発明が解決しようとする課題】
しかしながら、従来のスクリーン印刷マスク５３において、印刷領域５４の周縁部５４ａは、印刷領域５４と非印刷領域５５の境界部分であり、不連続な版離れが生じ易い領域である。従って、この不連続な版離れにより、周縁部５４ａの開口部５６によって形成される内部電極面積や塗布厚などは、周縁部５４ａによって囲まれた内側部５４ｂの開口部５６によって形成される内部電極と比較して、小さくかつ薄くなる傾向があった。この結果、周縁部５４ａの開口部５６によって形成される内部電極の歩留まりは悪かった。
【０００５】
そこで、本発明の目的は、印刷領域全体に渡って、均一な印刷パターン面積や塗布厚が得られるスクリーン印刷版を提供することにある。
【０００６】
【課題を解決するための手段および作用】
前記目的を達成するため、本発明に係るスクリーン印刷版は、メッシュ部と図形部とを備え、メッシュ部には、略規則的に配置された複数の孔が設けられ、図形部には、同一の図形を所定のピッチで複数配置した印刷パターンに対応する平面形状を有する複数の凹部が設けられている。
【０００７】
そして、複数の凹部が設けられた印刷領域の周縁部に配置されているメッシュ部の開口率が、周縁部に囲まれた内側部に配置されているメッシュ部の開口率より大きいことを特徴とする。ここに、印刷領域の周縁部の幅寸法は印刷領域の長さ寸法の２〜１０％となる寸法である。また、メッシュ部の開口率は、図形部に設けられた凹部の平面形状の面積に対する、メッシュ部に設けられた孔の開口面積の割合を意味する。つまり、孔径を大きくしたり、孔の数を増やしたりして、周縁部に配置されているメッシュ部の開口率を、内側部に配置されているメッシュ部の標準開口率より大きく設定する。これにより、周縁部の図形部の凹部へのペースト供給量が増加し、印刷パターン面積が大きくなるとともに、塗布厚が厚くなる。
【０００８】
また、複数の凹部が設けられた印刷領域の周縁部に配置されている凹部の平面形状が、周縁部に囲まれた内側部に配置されている凹部の平面形状より大きいことを特徴とする。これにより、周縁部に配置されている凹部の平面形状は、内側部に配置されている凹部の標準形状より大きく設定される。従って、周縁部の凹部の空間体積が増加し、印刷パターン面積が大きくなる。
【０００９】
また、複数の凹部が設けられた印刷領域の周縁部に配置されているメッシュ部の厚みを周縁部に囲まれた内側部に配置されているメッシュ部の厚みより薄くすることを特徴とする。これにより、ペーストのメッシュ通過性が向上してペースト供給量が増加し、印刷パターン面積が大きくなるとともに、塗布厚が厚くなる。
【００１０】
また、複数の凹部が設けられた印刷領域の周縁部に配置されている図形部の厚みを周縁部に囲まれた内側部に配置されている図形部の厚みより厚くすることを特徴とする。これにより、周縁部の凹部の空間体積が増加し、印刷パターン面積が大きくなるとともに、塗布厚が厚くなる。
【００１１】
【発明の実施の形態】
以下、本発明に係るスクリーン印刷版の実施形態について添付の図面を参照して説明する。なお、各実施形態は、積層セラミックコンデンサの内部電極をマザーセラミックグリーンシートに印刷する際に用いられるスクリーン印刷版を例にして説明するが、本発明はこれに限定されるものではないことは言うまでもない。
【００１２】
［第１実施形態、図１〜図４］
図１はスクリーン印刷版の下面図であり、図２はスクリーン印刷版を上面側から見た一部拡大斜視図である。このスクリーン印刷版は、額縁状の枠部材２の下面にスクリーン印刷マスク１が装着されている。スクリーン印刷マスク１の中央部分を囲む一点鎖線４は、印刷対象のマザーセラミックグリーンシートに応じて設定される印刷領域である。
【００１３】
スクリーン印刷マスク１は、図２に示すように、メッシュ部１６と図形部１７を厚み方向に備えた構造を有している。メッシュ部１６には、格子状に規則的に２次元配置された複数の矩形状孔１６ａが形成されている。図形部１７には、同一の図形を所定のピッチで複数配置した印刷パターンに対応する平面形状を有する複数の矩形状凹部１７ａが形成されている。凹部１７ａの平面形状は孔１６ａの平面形状（横断面形状）より大きく、かつ、凹部１７ａには複数の孔１６ａが連通している。孔１６ａと凹部１７ａは、電極形成部３（図２において点線で囲んで表示している）を構成している。一度の印刷で多数の内部電極をマザーセラミックグリーンシート上に形成できるように、スクリーン印刷マスク１の印刷領域４には、電極形成部３が格子状に多数配置されている。なお、図１において、電極形成部３はその一部しか表示されていない。
【００１４】
このスクリーン印刷マスク１は、例えば図３に示す製造方法により得られる。まず、工程（Ａ）に示すように、たとえばステンレス鋼からなる基材１８が用意される。この基材１８上には、第１のレジスト１９が形成される。第１のレジスト１９は、前述したメッシュ部１６の孔１６ａとなるべき位置に形成されるように、たとえばフォトリソグラフィによりパターニングされる。次に、工程（Ｂ）に示すように、基材１８上に、第１のレジスト１９の形成領域を除いて、たとえばニッケルからなるメッシュ部１６が電気めっきにより形成される。
【００１５】
次に、工程（Ｃ）に示すように、第１のレジスト１９およびメッシュ部１６上に、所望の印刷パターン（図形部１７の凹部１７ａの平面形状に相当するパターン）のネガパターンで第２のレジスト２１が形成される。この第２のレジスト２１のパターニングも、フォトリソグラフィにより行なわれる。次に、工程（Ｄ）に示すように、メッシュ部１６上に、第２のレジスト２１の形成領域を除いて、たとえばニッケルからなる図形部１７が電気めっきにより形成される。
【００１６】
次に、工程（Ｅ）に示すように、第１および第２のレジスト１９および２１が除去される。これにより、孔１６ａを有したメッシュ部１６と凹部１７ａを有した図形部１７とからなる２層構造体が形成される。メッシュ部１６の標準厚みは８〜９μｍ（代表値）、図形部１７の標準厚みは１６μｍ（代表値）である。また、孔１６ａの軸方向の長さＬと穴径Ｄのアスペクト比（Ｌ／Ｄ）を１以下にすれば、ペーストの充填性が良くなるので好ましい。
【００１７】
次に、工程（Ｆ）に示すように、基材１８からメッシュ部１６および図形部１７が一体的に剥離される。なお、この剥離は、基材１８がステンレス鋼から構成されているので、容易に行うことができる。このようにして、所望のスクリーン印刷マスク１が得られる。上述したスクリーン印刷マスク１の製造方法において、工程（Ｅ）と工程（Ｆ）の順序を逆にしてもよい。
【００１８】
ここで、図１に示すように、スクリーン印刷マスク１は、印刷領域４の周縁部４ａに配置されているメッシュ部１６の開口率が、周縁部４ａに囲まれた内側部４ｂに配置されているメッシュ部１６の標準開口率より大きく設定されている。メッシュ部１６の開口率は、凹部１７ａの平面形状の面積に対する、孔１６ａの開口面積の割合を意味する。通常、周縁部４ａに配置されているメッシュ部１６の孔１６ａの径を大きくしたり、数を多くしたりして、開口率を大きくする。この場合、導電性ペーストのマスク抜け性の変化を抑えるためには、図１に示すように、孔１６ａの数で開口率を調整する方が好ましい。
【００１９】
このようなスクリーン印刷マスク１を製作するには、周縁部４ａの孔１６ａとなるべき位置に形成される第１のレジスト１９の形成面積を標準より大きくしたり、数を多くしたりすればよい。これにより、周縁部４ａのメッシュ部１６の開口率が増加し、周縁部４ａの凹部１７ａへのペースト供給量が増加する。この結果、周縁部４ａの電極形成部３によって形成された内部電極の面積を大きくすることができるとともに、塗布厚を厚くすることができ、従来生じていた面積不足や塗布厚不足の不具合が解消される。
【００２０】
また、周縁部４ａの幅寸法Ｂ１，Ｂ２，Ｃ１，Ｃ２（図１参照）は、たとえば以下のようにして設定される。図４は、従来のスクリーン印刷マスク５１（全ての開口部５６の形状が同一であるもの）を用いてマザーセラミックグリーンシート上に形成した多数の内部電極の面積分布図の一例である。（Ａ）はＡ１方向（スキージ掃引方向）の面積分布図であり、（Ｂ）はＡ２方向（スキージ掃引方向と直交する方向）の面積分布図である。この分布図から、内部電極の面積が目標値以下の、特に高い効果が得られる部分（Ｂ１，Ｂ２，Ｃ１，Ｃ２にて表示した部分）を周縁部４ａとする。通常、周縁部４ａの幅寸法Ｂ１，Ｂ２およびＣ１，Ｃ２は、それぞれ印刷領域４の長さ寸法Ａ１，Ａ２の２〜１０％に設定される。言い換えると、図４の例においては周縁部４ａの幅寸法Ｂ１〜Ｃ２は、電極形成部３（凹部１７ａ）が５〜９個含まれる寸法である。
【００２１】
なお、図４から明らかなように、周縁部４ａに囲まれた内側部４ｂについては、所望の電極面積が得られている。従って、内側部４ｂのメッシュ部１６の開口率は一定とすることが好ましい。内側部４ｂのメッシュ部１６の開口率を例えば外側に向けて大きくすると、スクリーン印刷マスク１を枠部材２に張設したときに、外側領域のメッシュ部１６の応力が中心領域のメッシュ部１６の応力よりも大きくなり、外側領域の歪みが大きくなってしまう。内側部４ｂのメッシュ部１６の開口率を一定とすることにより、応力が分散するのでメッシュ部１６の歪みが小さくなる。
【００２２】
一方、本第１実施形態では、周縁部４ａのそれぞれの電極形成部３のメッシュ部１６の開口率を全て一律に大きくしているが、必ずしもこれに限るものではない。図４からも明らかなように、周縁部４ａの中でもさらに外側の方が電極面積が小さいので、周縁部４ａのそれぞれの電極形成部３のメッシュ部１６の開口率が、周縁部４ａの内側から外側に向かって除々に、あるいは段階的に順次大きくなるように設定することが好ましい。例えば、内側部４ｂのそれぞれの電極形成部３のメッシュ部１６の標準開口率が２０％で、周縁部４ａの最外周に位置する電極形成部３のメッシュ部１６の開口率が３０％である場合、最外周から順に３０％、２９％、２８％、…、２０％とする。
【００２３】
［第２実施形態、図５］
図５はスクリーン印刷版の下面図である。このスクリーン印刷版は、額縁状の枠部材２の下面にスクリーン印刷マスク１Ａが装着されている。スクリーン印刷マスク１Ａは、図１および図２に示したスクリーン印刷マスク１と同様に、孔１６ａを有したメッシュ部１６と凹部１７ａを有した図形部１７を厚み方向に備えた構造を有している。
【００２４】
ここで、スクリーン印刷マスク１Ａは、複数の凹部１７ａが設けられた印刷領域４の周縁部４ａに配置されている凹部１７ａの平面形状が、周縁部４ａに囲まれた内側部４ｂに配置されている凹部１７ａの平面形状より大きく設定されている。つまり、内側部４ｂに配置されている凹部１７ａの平面形状を所望のパターン形状に合わせて標準寸法にするのに対して、周縁部４ａに配置されている凹部１７ａの平面形状を標準寸法より大きくする。通常、周縁部４ａに配置されている凹部１７ａの面積が、内側部４ｂに配置されている凹部１７ａの面積より１〜１０％程度大きくなるようにする。
【００２５】
このようなスクリーン印刷マスク１Ａを製作するには、周縁部４ａの凹部１７ａとなるべき位置に形成される第２のレジスト２１の形成領域を、標準寸法面積より１０％程度大きくすればよい。これにより、周縁部４ａの凹部１７ａの空間体積が増加し、印刷パターン面積を大きくすることができる。従って、周縁部４ａの電極形成部３によって形成された内部電極は、従来生じていた面積不足の不具合が解消される。この結果、印刷領域４の全体に渡って均一な内部電極面積が得られる。
【００２６】
なお、本第２実施形態では、周縁部４ａの凹部１７ａの平面形状面積を全て一律１０％程度大きくしているが、必ずしもこれに限るものではない。周縁部４ａと内側部４ｂの内部電極の面積差が大きい場合には、周縁部４ａの凹部１７ａの平面形状面積が、周縁部４ａの内側から外側に向かって除々に、あるいは段階的に順次大きくなるように設定してもよい。これにより、内部電極の面積の均一化がより高精度にできる。
【００２７】
［第３実施形態、図６］
図６はスクリーン印刷版の下面図である。このスクリーン印刷版は、額縁状の枠部材２の下面にスクリーン印刷マスク１Ｂが装着されている。スクリーン印刷マスク１Ｂは、図１および図２に示したスクリーン印刷マスク１と同様に、孔１６ａを有したメッシュ部１６と凹部１７ａを有した図形部１７を厚み方向に備えた構造を有している。
【００２８】
ここで、スクリーン印刷マスク１Ｂは、図６に断面図で示すように、複数の凹部１７ａが設けられた印刷領域４の周縁部４ａに配置されているメッシュ部１６の厚みＴ２が、周縁部４ａに囲まれた内側部４ｂに配置されているメッシュ部１６の標準厚みＴ１より薄く、かつ、図形部１７の厚みｔ２がｔ１よりも厚く設定されている（Ｔ２＋ｔ２＝Ｔ１＋ｔ１）。
【００２９】
このようなスクリーン印刷マスク１Ｂを製作するには、メッシュ部１６の電気めっきの途中で、周縁部４ａをマスキングしてメッシュ部１６のめっきを制限するとともに、図形部１７の電気めっきの途中で、内側部４ｂをマスキングして図形部１７のめっきを制限すればよい。これによりメッシュ部１６のペースト通過性が向上し、かつ、周縁部４ａの凹部１７ａの空間体積が増加し、凹部１７ａに供給されるペースト量が多くなる。この結果、周縁部４ａの電極形成部３によって形成された内部電極の面積を大きくすることができるとともに、塗布厚を厚くすることができ、従来生じていた面積不足や塗布厚不足の不具合が解消される。
【００３０】
なお、本第３実施形態では、周縁部４ａのそれぞれの電極形成部３のメッシュ部１６の厚みＴ２を全て一律に薄くしているが、必ずしもこれに限るものではない。周縁部４ａのそれぞれの電極形成部３のメッシュ部１６の厚みＴ２が、周縁部４ａの内側から外側に向かって除々に、あるいは段階的に順次薄くなるように設定してもよい。
【００３１】
［他の実施形態］
なお、本発明に係るスクリーン印刷版は、前記実施形態に限定するものではなく、その要旨の範囲内で種々に変更することができる。例えば、メッシュ部の孔は横断面が矩形に限るものではなく、円形のものなど任意の形状のものが選択される。図形部の凹部の平面形状も任意である。
【００３２】
また、前記第３実施形態では、周縁部４ａのマスク厚（Ｔ２＋ｔ２）と内側部４ｂのマスク厚（Ｔ１＋ｔ１）が等しいものについて説明したが、周縁部４ａのマスク厚（Ｔ２＋ｔ２）を内側部４ｂのマスク厚（Ｔ１＋ｔ１）と異なる厚みとしたものであってもよい。さらに、前記第１〜第３実施形態を適宜組み合わせてもよい。
【００３３】
【発明の効果】
以上の説明で明らかなように、本発明によれば、周縁部の図形部の凹部へのペースト充填率が増加し、印刷パターン面積が大きくなるとともに、塗布厚が厚くなる。この結果、印刷領域全体に渡って均一な面積や塗布厚を有する印刷パターンを形成することができるスクリーン印刷版が得られる。
【図面の簡単な説明】
【図１】本発明に係るスクリーン印刷版の第１実施形態を示す下面図。
【図２】図１に示したスクリーン印刷版を上面側から見た一部拡大斜視図。
【図３】図１に示したスクリーン印刷マスクの製造方法の一例を示す断面図。
【図４】印刷領域の周縁部の幅寸法を決定するための内部電極の面積分布図。
【図５】本発明に係るスクリーン印刷版の第２実施形態を示す下面図。
【図６】本発明に係るスクリーン印刷版の第３実施形態を示す下面図。
【図７】従来のスクリーン印刷版を示す下面図。
【符号の説明】
１，１Ａ，１Ｂ…スクリーン印刷マスク
３…電極形成部
４…印刷領域
４ａ…周縁部
４ｂ…内側部
１６…メッシュ部
１６ａ…孔
１７…図形部
１７ａ…凹部[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a screen printing plate, for example, a screen printing plate used when printing an internal electrode of an electronic component on a ceramic green sheet.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, as a screen printing plate used for printing internal electrodes of an electronic component on a mother ceramic green sheet, for example, a screen printing plate shown in FIG. 7 is known. FIG. 7 is a view of the screen printing plate 51 viewed from the lower surface side. The screen printing plate 51 has a screen printing mask 53 mounted on the lower surface of a frame-shaped frame member 52. An alternate long and short dash line 54 surrounding the central portion of the screen print mask 53 is a printing area set according to a printing target (mother ceramic green sheet) to be printed. A large number of openings 56 are formed in the print area 54 for forming a print pattern by applying a conductive paste to a desired position on a printing medium. The shape of each opening 56 is the same. In FIG. 7, only a part of the opening 56 is shown.
[0003]
The screen printing plate 51 having the above configuration is set in a state where the lower surface thereof is separated from the upper surface of the printing table of the screen printing apparatus by a predetermined gap size, that is, in an off-contact state. A squeegee is arranged on the upper surface of the screen printing mask 53. In screen printing, the conductive paste supplied on the screen printing mask 53 is scraped by a squeegee, swept in a predetermined direction, and pushed into the opening 56 of the screen printing mask 53, thereby being placed on the printing table. A conductive paste is applied to a desired position on the printed substrate.
[0004]
[Problems to be solved by the invention]
However, in the conventional screen printing mask 53, the peripheral portion 54a of the printing region 54 is a boundary portion between the printing region 54 and the non-printing region 55, and is a region where discontinuous plate separation is likely to occur. Therefore, due to the discontinuous separation of the plate, the area and the coating thickness of the internal electrode formed by the opening 56 of the peripheral portion 54a are reduced by the internal electrode formed by the opening 56 of the inner portion 54b surrounded by the peripheral portion 54a. As compared with, there was a tendency to be small and thin. As a result, the yield of the internal electrodes formed by the openings 56 in the peripheral portion 54a was poor.
[0005]
Therefore, an object of the present invention is to provide a screen printing plate capable of obtaining a uniform printing pattern area and a uniform coating thickness over the entire printing area.
[0006]
Means and action for solving the problem
In order to achieve the above object, a screen printing plate according to the present invention includes a mesh part and a graphic part, and the mesh part is provided with a plurality of holes arranged substantially regularly, and the graphic part has the same shape. Are provided with a plurality of concave portions having a planar shape corresponding to a print pattern in which a plurality of figures are arranged at a predetermined pitch.
[0007]
And the aperture ratio of the mesh portion arranged at the peripheral portion of the printing area provided with the plurality of concave portions is larger than the aperture ratio of the mesh portion disposed at the inner portion surrounded by the peripheral portion. I do. Here, the width dimension of the peripheral portion of the printing area is a dimension that is 2 to 10% of the length dimension of the printing area. The aperture ratio of the mesh portion means a ratio of the opening area of the hole provided in the mesh portion to the area of the planar shape of the concave portion provided in the graphic portion. That is, by increasing the hole diameter or increasing the number of holes, the aperture ratio of the mesh portion disposed on the peripheral portion is set to be larger than the standard aperture ratio of the mesh portion disposed on the inner side. As a result, the amount of paste supplied to the concave portion of the graphic portion at the peripheral portion increases, the print pattern area increases, and the coating thickness increases.
[0008]
Further, the planar shape of the concave portion arranged at the peripheral portion of the printing region provided with the plurality of concave portions is larger than the planar shape of the concave portion arranged at the inner portion surrounded by the peripheral portion. Thereby, the planar shape of the concave portion disposed on the peripheral portion is set to be larger than the standard shape of the concave portion disposed on the inner side. Therefore, the space volume of the concave portion at the peripheral edge increases, and the print pattern area increases.
[0009]
Further, the thickness of the mesh portion disposed at the peripheral portion of the printing region provided with the plurality of concave portions is made smaller than the thickness of the mesh portion disposed at the inner portion surrounded by the peripheral portion. As a result, the mesh permeability of the paste is improved, the amount of the supplied paste is increased, the print pattern area is increased, and the coating thickness is increased.
[0010]
Further, the thickness of the graphic portion arranged on the peripheral portion of the printing area provided with the plurality of concave portions is made thicker than the thickness of the graphic portion arranged on the inner portion surrounded by the peripheral portion. Thereby, the space volume of the concave portion at the peripheral edge increases, the print pattern area increases, and the coating thickness increases.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of a screen printing plate according to the present invention will be described with reference to the accompanying drawings. In each embodiment, a screen printing plate used when printing the internal electrodes of the multilayer ceramic capacitor on the mother ceramic green sheet will be described as an example, but it goes without saying that the present invention is not limited to this. No.
[0012]
[First Embodiment, FIGS. 1 to 4]
FIG. 1 is a bottom view of the screen printing plate, and FIG. 2 is a partially enlarged perspective view of the screen printing plate as viewed from above. In this screen printing plate, a screen printing mask 1 is mounted on a lower surface of a frame member 2 having a frame shape. A dashed line 4 surrounding the central portion of the screen printing mask 1 is a printing area set according to the mother ceramic green sheet to be printed.
[0013]
As shown in FIG. 2, the screen printing mask 1 has a structure including a mesh portion 16 and a graphic portion 17 in the thickness direction. The mesh part 16 is formed with a plurality of rectangular holes 16a regularly two-dimensionally arranged in a lattice. In the figure portion 17, a plurality of rectangular concave portions 17a having a planar shape corresponding to a print pattern in which a plurality of the same figures are arranged at a predetermined pitch are formed. The planar shape of the concave portion 17a is larger than the planar shape (cross-sectional shape) of the hole 16a, and a plurality of holes 16a communicate with the concave portion 17a. The hole 16a and the concave portion 17a constitute the electrode forming portion 3 (shown by being surrounded by a dotted line in FIG. 2). In the printing area 4 of the screen printing mask 1, a large number of electrode forming portions 3 are arranged in a grid so that a large number of internal electrodes can be formed on the mother ceramic green sheet by one printing. In FIG. 1, only a part of the electrode forming portion 3 is shown.
[0014]
This screen printing mask 1 is obtained, for example, by the manufacturing method shown in FIG. First, as shown in the step (A), a substrate 18 made of, for example, stainless steel is prepared. On this base material 18, a first resist 19 is formed. The first resist 19 is patterned by, for example, photolithography so as to be formed at a position to be the hole 16a of the mesh portion 16 described above. Next, as shown in step (B), a mesh portion 16 made of, for example, nickel is formed on the base material 18 except for a region where the first resist 19 is formed by electroplating.
[0015]
Next, as shown in step (C), a second negative pattern of a desired print pattern (a pattern corresponding to the planar shape of the concave portion 17 a of the graphic portion 17) is formed on the first resist 19 and the mesh portion 16. A resist 21 is formed. The patterning of the second resist 21 is also performed by photolithography. Next, as shown in the step (D), a figure portion 17 made of, for example, nickel is formed on the mesh portion 16 by electroplating except for a region where the second resist 21 is formed.
[0016]
Next, as shown in step (E), the first and second resists 19 and 21 are removed. Thus, a two-layer structure including the mesh portion 16 having the holes 16a and the graphic portion 17 having the concave portions 17a is formed. The standard thickness of the mesh portion 16 is 8 to 9 μm (representative value), and the standard thickness of the graphic portion 17 is 16 μm (representative value). Further, it is preferable to set the aspect ratio (L / D) of the length L in the axial direction of the hole 16a and the diameter D of the hole to 1 or less, because the filling property of the paste is improved.
[0017]
Next, as shown in step (F), the mesh portion 16 and the graphic portion 17 are integrally peeled from the base material 18. This peeling can be easily performed because the base material 18 is made of stainless steel. Thus, a desired screen printing mask 1 is obtained. In the method of manufacturing the screen printing mask 1 described above, the order of the step (E) and the step (F) may be reversed.
[0018]
Here, as shown in FIG. 1, in the screen printing mask 1, the aperture ratio of the mesh portion 16 arranged on the peripheral portion 4 a of the printing area 4 is arranged on the inner portion 4 b surrounded by the peripheral portion 4 a. The opening ratio is set to be larger than the standard aperture ratio of the mesh portion 16. The aperture ratio of the mesh portion 16 means the ratio of the opening area of the hole 16a to the area of the planar shape of the concave portion 17a. Usually, the diameter of the holes 16a of the mesh portion 16 arranged on the peripheral edge portion 4a is increased or the number thereof is increased to increase the aperture ratio. In this case, in order to suppress a change in the masking property of the conductive paste, it is preferable to adjust the aperture ratio by the number of the holes 16a as shown in FIG.
[0019]
In order to manufacture such a screen printing mask 1, the formation area of the first resist 19 formed at the position to be the hole 16a of the peripheral portion 4a may be made larger than the standard or the number thereof may be increased. . Thus, the aperture ratio of the mesh portion 16 in the peripheral portion 4a increases, and the amount of paste supplied to the concave portion 17a in the peripheral portion 4a increases. As a result, the area of the internal electrode formed by the electrode forming portion 3 in the peripheral portion 4a can be increased, and the coating thickness can be increased, thereby solving the problems of the area shortage and the coating thickness shortage which have conventionally occurred. Is done.
[0020]
The widths B1, B2, C1, and C2 (see FIG. 1) of the peripheral portion 4a are set, for example, as follows. FIG. 4 is an example of an area distribution diagram of a large number of internal electrodes formed on a mother ceramic green sheet using a conventional screen printing mask 51 (all openings 56 have the same shape). (A) is an area distribution diagram in the A1 direction (squeegee sweep direction), and (B) is an area distribution diagram in the A2 direction (direction orthogonal to the squeegee sweep direction). From this distribution diagram, a portion where the area of the internal electrode is equal to or smaller than the target value and a particularly high effect is obtained (the portion indicated by B1, B2, C1, and C2) is defined as the peripheral portion 4a. Normally, the widths B1, B2 and C1, C2 of the peripheral portion 4a are set to 2 to 10% of the lengths A1, A2 of the print area 4, respectively. In other words, in the example of FIG. 4, the width dimension B1 to C2 of the peripheral edge 4a is a dimension including 5 to 9 electrode forming portions 3 (recesses 17a).
[0021]
As is clear from FIG. 4, a desired electrode area is obtained for the inner portion 4b surrounded by the peripheral portion 4a. Therefore, it is preferable that the aperture ratio of the mesh portion 16 of the inner portion 4b be constant. When the aperture ratio of the mesh portion 16 of the inner portion 4b is increased, for example, toward the outside, when the screen printing mask 1 is stretched on the frame member 2, the stress of the mesh portion 16 in the outer region becomes smaller than that of the mesh portion 16 in the center region. It becomes larger than the stress, and the strain in the outer region becomes larger. By keeping the aperture ratio of the mesh portion 16 of the inner portion 4b constant, the stress is dispersed, so that the distortion of the mesh portion 16 is reduced.
[0022]
On the other hand, in the first embodiment, the aperture ratios of the mesh portions 16 of the respective electrode forming portions 3 of the peripheral portion 4a are all uniformly increased, but the invention is not necessarily limited to this. As is clear from FIG. 4, since the electrode area is further smaller on the outer side of the peripheral portion 4 a, the aperture ratio of the mesh portion 16 of each electrode forming portion 3 of the peripheral portion 4 a is reduced from the inside of the peripheral portion 4 a. It is preferable to set so as to gradually increase toward the outside or to increase gradually. For example, the standard aperture ratio of the mesh portion 16 of each electrode forming portion 3 of the inner portion 4b is 20%, and the aperture ratio of the mesh portion 16 of the electrode forming portion 3 located at the outermost periphery of the peripheral portion 4a is 30%. In this case, 30%, 29%, 28%,..., 20% are set in order from the outermost periphery.
[0023]
[Second embodiment, FIG. 5]
FIG. 5 is a bottom view of the screen printing plate. In this screen printing plate, a screen printing mask 1A is mounted on the lower surface of a frame member 2 having a frame shape. The screen printing mask 1A has a structure in which a mesh portion 16 having a hole 16a and a graphic portion 17 having a concave portion 17a are provided in the thickness direction similarly to the screen printing mask 1 shown in FIGS. I have.
[0024]
Here, in the screen printing mask 1A, the planar shape of the concave portion 17a disposed on the peripheral portion 4a of the printing region 4 provided with the plurality of concave portions 17a is disposed on the inner portion 4b surrounded by the peripheral portion 4a. It is set to be larger than the planar shape of the recess 17a. In other words, while the planar shape of the concave portion 17a disposed on the inner portion 4b is set to the standard size according to the desired pattern shape, the planar shape of the concave portion 17a disposed on the peripheral portion 4a is larger than the standard size. I do. Normally, the area of the concave portion 17a arranged on the peripheral portion 4a is set to be about 1 to 10% larger than the area of the concave portion 17a arranged on the inner portion 4b.
[0025]
In order to manufacture such a screen printing mask 1A, the formation region of the second resist 21 formed at a position to be the concave portion 17a of the peripheral portion 4a may be made about 10% larger than the standard dimension area. Thereby, the space volume of the concave portion 17a of the peripheral portion 4a increases, and the print pattern area can be increased. Therefore, the problem of the shortage of the area, which has conventionally occurred, in the internal electrode formed by the electrode forming portion 3 of the peripheral portion 4a is solved. As a result, a uniform internal electrode area can be obtained over the entire printing area 4.
[0026]
In the second embodiment, the planar shape area of the concave portion 17a of the peripheral portion 4a is uniformly increased by about 10%, but is not necessarily limited to this. When the area difference between the internal electrodes of the peripheral portion 4a and the inner portion 4b is large, the planar shape area of the concave portion 17a of the peripheral portion 4a gradually or gradually increases from the inside to the outside of the peripheral portion 4a. May be set. Thereby, the area of the internal electrodes can be made uniform with higher accuracy.
[0027]
[Third embodiment, FIG. 6]
FIG. 6 is a bottom view of the screen printing plate. In this screen printing plate, a screen printing mask 1B is mounted on a lower surface of a frame member 2 having a frame shape. The screen printing mask 1B has a structure in which a mesh portion 16 having a hole 16a and a graphic portion 17 having a concave portion 17a are provided in the thickness direction similarly to the screen printing mask 1 shown in FIGS. I have.
[0028]
Here, as shown in the cross-sectional view of FIG. 6, the screen printing mask 1B has a thickness T2 of the mesh portion 16 arranged on the peripheral portion 4a of the printing region 4 in which the plurality of recesses 17a are provided. Are set to be smaller than the standard thickness T1 of the mesh portion 16 disposed in the inner portion 4b surrounded by, and the thickness t2 of the graphic portion 17 is set to be larger than t1 (T2 + t2 = T1 + t1).
[0029]
In order to manufacture such a screen printing mask 1B, in the middle of the electroplating of the mesh portion 16, the peripheral portion 4a is masked to limit the plating of the mesh portion 16, and in the middle of the electroplating of the graphic portion 17, The plating of the graphic portion 17 may be limited by masking the inner portion 4b. As a result, the paste passage property of the mesh portion 16 is improved, the space volume of the concave portion 17a of the peripheral portion 4a is increased, and the amount of paste supplied to the concave portion 17a is increased. As a result, the area of the internal electrode formed by the electrode forming portion 3 in the peripheral portion 4a can be increased, and the coating thickness can be increased, thereby solving the problems of the area shortage and the coating thickness shortage which have conventionally occurred. Is done.
[0030]
In the third embodiment, the thickness T2 of the mesh portion 16 of each of the electrode forming portions 3 of the peripheral portion 4a is uniformly reduced, but is not necessarily limited to this. The thickness T2 of the mesh portion 16 of each of the electrode forming portions 3 of the peripheral portion 4a may be set so as to gradually or gradually decrease from the inside to the outside of the peripheral portion 4a.
[0031]
[Other embodiments]
The screen printing plate according to the present invention is not limited to the above embodiment, and can be variously changed within the scope of the gist. For example, the holes of the mesh portion are not limited to a rectangular cross-section, but may be any shape such as a circular one. The planar shape of the concave portion of the figure portion is also arbitrary.
[0032]
In the third embodiment, the mask thickness (T2 + t2) of the peripheral portion 4a is equal to the mask thickness (T1 + t1) of the inner portion 4b. However, the mask thickness (T2 + t2) of the peripheral portion 4a is set to The thickness may be different from the mask thickness (T1 + t1). Further, the first to third embodiments may be appropriately combined.
[0033]
【The invention's effect】
As apparent from the above description, according to the present invention, the filling rate of the paste into the concave portion of the graphic portion at the peripheral portion increases, the print pattern area increases, and the coating thickness increases. As a result, a screen printing plate capable of forming a printing pattern having a uniform area and a uniform coating thickness over the entire printing region is obtained.
[Brief description of the drawings]
FIG. 1 is a bottom view showing a first embodiment of a screen printing plate according to the present invention.
FIG. 2 is a partially enlarged perspective view of the screen printing plate shown in FIG. 1 as viewed from above.
FIG. 3 is a sectional view showing an example of a method for manufacturing the screen printing mask shown in FIG.
FIG. 4 is an area distribution diagram of internal electrodes for determining a width dimension of a peripheral portion of a printing region.
FIG. 5 is a bottom view showing a second embodiment of the screen printing plate according to the present invention.
FIG. 6 is a bottom view showing a third embodiment of the screen printing plate according to the present invention.
FIG. 7 is a bottom view showing a conventional screen printing plate.
[Explanation of symbols]
1, 1A, 1B ... screen printing mask 3 ... electrode forming part 4 ... printing area 4a ... peripheral part 4b ... inner part 16 ... mesh part 16a ... hole 17 ... figure part 17a ... concave part

Claims

It has a mesh part and a figure part,
The mesh portion is provided with a plurality of holes arranged substantially regularly,
The figure portion is provided with a plurality of recesses having a planar shape corresponding to a print pattern in which a plurality of the same figures are arranged at a predetermined pitch,
The aperture ratio of the mesh portion disposed on the peripheral portion of the print area provided with the plurality of recesses is larger than the aperture ratio of the mesh portion disposed on the inner portion surrounded by the peripheral portion,
Screen printing plate characterized by the following.

2. The screen printing plate according to claim 1, wherein an aperture ratio of a mesh portion arranged at a peripheral portion of the printing region increases in order from inside to outside of the peripheral portion. 3.

It has a mesh part and a figure part,
The mesh portion is provided with a plurality of holes arranged substantially regularly,
The figure portion is provided with a plurality of recesses having a planar shape corresponding to a print pattern in which a plurality of the same figures are arranged at a predetermined pitch,
The planar shape of the concave portion arranged at the peripheral portion of the printing area provided with the plurality of concave portions is larger than the planar shape of the concave portion arranged at the inner portion surrounded by the peripheral portion,
Screen printing plate characterized by the following.

4. The screen printing plate according to claim 3, wherein a planar shape area of the concave portion arranged at a peripheral portion of the printing region is gradually increased from inside to outside of the peripheral portion. 5.

It has a mesh part and a figure part,
The mesh portion is provided with a plurality of holes arranged substantially regularly,
The figure portion is provided with a plurality of recesses having a planar shape corresponding to a print pattern in which a plurality of the same figures are arranged at a predetermined pitch,
The thickness of the mesh portion disposed at the peripheral portion of the printing region provided with the plurality of recesses is smaller than the thickness of the mesh portion disposed at the inner portion surrounded by the peripheral portion, and the plurality of The thickness of the graphic portion disposed on the peripheral portion of the printing area provided with the concave portion is thicker than the thickness of the graphic portion disposed on the inner portion surrounded by the peripheral portion,
Screen printing plate characterized by the following.

The thickness of the mesh portion disposed at the peripheral portion of the printing region is gradually reduced from the inside to the outside of the peripheral portion, or the thickness of the graphic portion disposed at the peripheral portion of the printing region. The screen printing plate according to claim 5, wherein the thickness of the screen printing plate gradually increases from the inside to the outside of the peripheral portion.

The planar shape of the concave portion of the figure portion is larger than the planar shape of the hole of the mesh portion, and at least two of the holes communicate with the concave portion. Screen printing plate described in Crab.

The screen printing plate according to any one of claims 1 to 7, wherein a width dimension of a peripheral portion of the printing area is 2 to 10% of a length dimension of the printing area.

At least one of an aperture ratio of a mesh portion of an inner portion surrounded by a peripheral portion of the printing region, a planar shape of a concave portion, and a thickness of a graphic portion is constant over the entire area of the inner portion. A screen printing plate according to any one of claims 1 to 8.