JP2004299092A - Method for manufacturing printing plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a printing plate capable of (1) forming a printing plate pattern without generating a developing liquid and an etching liquid like a photo-lithographic method and generating a situation for hardly corresponding to a requirement of an on-demand type production, (2) obtaining an enough smoothness of an inner wall even on a fine through-opening and a recessed part, and (3) avoiding exchanging of a laser oscillator provided with an expensive gas leakage preventing mechanism, and cost up caused by decrease in a processing speed by an intermittent shot processing. <P>SOLUTION: As a laser processing for forming the through-opening and the recessed part, a CO<SB>2</SB>laser processing is used, and as a thin sheet 101 of an object to be processed, a product with a base layer composed of an acrylic resin is used. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００１８】
表１に示すように、アクリル、ＰＣ又はＰＥＴをＣＯ_２レーザー加工して得られた幅約５０［μｍ］というファインピッチな貫通開口は、十分な内壁平滑性を発揮することがわかる。なお、加工時におけるアシストガスについては、圧０．５［ｋｇ／ｃｍ^２］のＡｉｒを用いたが、加工対象物としてアクリルを用いた場合にはアシストガスを使用しないても同等の結果が得られた。
【００１９】
次に、本印刷版製造方法の具体的な内容について説明する。
図１は、本印刷版製造方法に用いるレーザー加工装置を示す概略構成図である。このレーザー加工装置は、ＣＯ_２レーザー装置１、フェムト秒レーザー装置４、ＸＹテーブル２、メインコントローラ３などを備えている。メインコントローラ３は、レーザー加工装置の全体の制御を司るものであり、ＣＯ_２レーザー装置１、フェムト秒レーザー装置４、後述のテーブルコントローラ２２等に電気的に接続されている。
【００２０】
上記ＸＹテーブル２上には、ワーク１００が保持されている。このワーク１００は、アクリルからなる基層に、導電性材料からなる表面層が被覆された加工対象物たる薄板１０１と、これのレーザー照射面とは反対側の面（以下、裏面という）の縁に固定された枠体１０２とを有している。ＸＹテーブル２は、図示しないクリップ機構によってワーク１００の枠体１０２をクリップすることで、ワーク保持台２０上にワーク１００を保持するようになっている。ワーク保持台２０は、Ｘ−Ｙ方向に移動することで、各レーザー装置から発せられるレーザー光の薄板１０１に対する照射ポイントを変化させる。このワーク保持台２０の移動は、ＸＹテーブル２のテーブルコントローラ２２によって制御される。
【００２１】
上記ＣＯ_２レーザー装置１は、ＣＯ_２レーザー発振器１０と、加工ヘッド１１とを有している。ＣＯ_２レーザー発振器１０から発振されたＣＯ_２レーザー光ｃＬは、図示しない反射ミラーや集光レンズなどを有する加工ヘッド１１を経て、ワーク１００の薄板１０１に照射される。このとき、加工ヘッド１１の図示しないガス受入口にアシストガスが圧入されると、ＣＯ_２レーザーとともにアシストガスが加工ヘッド１１から噴射される。ＣＯ_２レーザー光ｃＬの照射により、薄板１０１には直径約５０［μｍ］の貫通孔が形成される。貫通孔ではなく、幅約５０［μｍ］の長穴が形成される場合には、ＣＯ_２レーザーｃＬが連続照射されながら、ワーク１００がＸＹテーブル２上で移動せしめられる。
【００２２】
上記フェムト秒レーザー装置４は、フェムト秒レーザー発振器４０と、加工ヘッド４１とを有している。フェムト秒レーザー発振器４０は、可視領域の波長のフェムト秒レーザー光ｆＬを発振する。発振されたフェムト秒レーザー光ｆＬは、図示しないアパーチャ、落射ミラー、集光レンズなどを有する加工ヘッド４１を経て、ワーク１００の薄板１０１に照射される。フェムト秒レーザー光ｆＬは、１ピコ秒以下のパルス放射時間で出力されるレーザーであり、例えば、レーザー光波長７７５［ｎｍ］、パルス放射時間１５０［フェムト秒］以下、最大エネルギー８００［μＪ／パルス］のものである。これによれば、放射光のエネルギー密度が発振パルスにおいて数ギガワットのレベルに達し、時間的エネルギー密度が飛躍的に高まるため、複数の光子が同時に吸収される多光子吸収過程が起こる。そして、遠紫外線等のフォトンエネルギーが大きい光子でしか吸収が起こらなかった材料に対しても、複数光子の同時吸収といった形態でエネルギーを吸収せしめ、アブレーション現象を生起させることができる。また、レーザー照射時間が非常に短いため、レーザー光が熱エネルギーとして被加工物内を拡散する前に、昇華アブレーション加工プロセスが終了する。また、フェムト秒レーザー光ｆＬが可視領域の波長であり容易に視認されるため、加工用の他に、光軸合わせ時の光路ガイド光として兼用可能になる。
【００２３】
図２は、ＸＹテーブル２の要部を示す側面図である。同図において、ＸＹテーブル２は、図示しない各レーザー装置の加工ヘッド（図１の１１、４１）に対して、ワーク１００が保持されたワーク保持台２０をＸ軸方向（図中奥行き方向）及びＹ軸方向（図中左右方向）に相対移動させる。具体的には、ワーク保持台２０の下面には、図中奥行き方向に延在するＸ溝が形成された脚２３が２つ固定されている。また、ワーク保持台２０の図中下方には、Ｙ軸移動台２４が配設されている。このＹ軸移動台２４の上面には、図中奥行き方向に延在するＸガイドレール２５が２つ固定されている。ワーク保持台２０は、その下面に固定された２つの脚２３のＸ溝を、それぞれＸガイドレール２５に係合させるようにレール上に載置されることで、Ｙ軸移動台２４に支持される。ワーク保持台２０とＹ軸移動台２４との間には、リニアモータ２６が設けられている。このリニアモータ２６は、ワーク保持台２０の下面に固定された下面電極部２６ａと、これに対向するようにＹ軸移動台２４の上面に固定された上面電極部２６ｂとを有している。これら電極部が励磁されると、図中Ｘ軸方向に向かう電磁力がワーク保持台２０に作用する。これにより、ワーク保持台２０がＸガイドレール２５に沿ってＸ軸方向に移動する。Ｙ軸移動台２４は、図示しない支持部上に支持されており、ワーク保持台２０をＸ軸方向に移動させるのと同様の機構により、支持部上でＹ軸方向に移動するようになっている。
【００２４】
Ｘ軸移動台２４の上面には、それぞれ図中Ｘ軸方向に延在するメイン凸部２７ａ、サブ凸部２７ｂが設けられている。メイン凸部２７ａの側面、サブ凸部２７ｂの側面には、それぞれメインリニアスケール２８ａ、サブリニアスケール２８ｂが固定されている。これらスケールは、Ｘ軸方向に刻まれた目盛り図示しない目盛りを有している。一方、ワーク保持台２０の下面には、メイン位置検出センサ２９ａと、サブ位置検出センサ２９ｂとが、それぞれメインリニアスケール２８ａ、サブリニアスケール２８ｂの目盛りを読み取ることができるように固定されている。これら位置検出センサとしては、例えば反射型フォトセンサを用いることができる。メイン位置検出センサ２９ａは、メインリニアスケール２８ａの目盛りによって得られたＯＮ／ＯＦＦ信号を、テーブルコントローラ２２に出力する。テーブルコントローラ２２は、この信号に基づいてリニアモータ２６に対する励磁を制御し、フェムト秒レーザ光ｆＬに対してワーク１００をＸ軸方向に相対移動させる。また、サブ位置検出センサ２９ｂはサブリニアスケール２８ｂの目盛りによって得られたＯＮ／ＯＦＦ信号をテーブルコントローラ２２及びメインコントローラ（図１の３）に出力する。メインコントローラはこの信号に基づいて各レーザー発振器（図１の１０、４０）を制御して、各レーザーを発振させる。なお、このレーザー加工装置では、Ｙ軸方向については、メイン位置検出センサとメインリニアスケールとを対向させて配設しているが、サブ位置検出センサとサブリニアスケールとは設けていない。
【００２５】
メイン位置検出センサ２９ａとしては分解能１［μｍ］のものが使用されており、メインリニアスケール２８ａとしては目盛り間隔０．１７［ｍｍ］のものが使用されている。一方、サブ位置検出センサ２９ｂとしては分解能０．１［μｍ］のものが使用されており、サブリニアスケール２８ｂとしては幅０．５［μｍ］の目盛りを０．１７［ｍｍ］間隔で備えるものが使用されている。これらリニアスケールとしては、例えば株式会社レニショー社製のものを用いることができる。メイン位置検出センサ２９ａからＯＮ信号が発生した直後にサブ位置検出センサ２８ｂから発せられるＯＮ信号が、各レーザー光のショット開始信号として用いられる。そして、サブ位置検出センサ２８ｂから発せられる次のＯＮ信号が各レーザー光のショット停止信号として用いられる。
【００２６】
図３は、上記レーザー加工装置によって貫通開口からなる版パターンが形成された印刷孔版たるプラスチックマスク１２０を示す拡大平面図である。このプラスチックマスク１２０は、電子回路基板にクリームはんだからなる電極パターンを印刷するためのものである。同図において、プラスチックマスク１２０の版パターンは、幅約１００［μｍ］の複数の貫通開口からなるファインピッチパターンＰａと、幅約５０［μｍ］の複数の貫通孔からなる超ファインピッチパターンＰｂとから構成されている。これらパターンのうち、ファインピッチパターンＰａは、ＣＯ_２レーザーによって面積加工されたものである。面積加工とは、例えば直径φの丸穴をレーザー加工する場合に、直径φにほぼ等しいレーザースポットによってその丸穴を一気に打ち抜く加工法である。一方、超ファインピッチパターンＰｂは、小さすぎてＣＯ_２レーザーでは加工ができないため、フェムト秒レーザーによって輪郭加工されたものである。輪郭加工とは、例えば直径φの丸穴をレーザー加工する場合に、直径φよりも小さいレーザースポットによってその丸穴の輪郭を切り抜いて丸穴を得る加工法である。糸ノコギリで丸穴を切り抜くような要領でレーザー加工するのである。
【００２７】
図４は、上記プラスチックマスク１２０を示す拡大断面図である。このプラスチックマスク１２０は、上述の薄板（１０１）に対してレーザー加工処理による版パターンが形成されたものである。この薄板（１０１）はアクリルからなる基層１０１ａと、チタン等の金属やカーボンなどといった導電性材料からなる表面層１０１ｂとを有している。かかる構成の薄板（１０１）に対してレーザー加工処理による版パターンが形成されたプラスチックマスク１２０では、印刷時にスキージー等の印刷材すり込み部材に繰り返し摩擦されても、電電性材料からなる表面層１０１ｂによって電荷を逃がすことができる。よって、印刷材すり込み時に摩擦帯電するようなことがない。
【００２８】
なお、導電性材料からなる表面層１０１ｂを設けるのではなく、プラスチックからなる基層１０１ａとしてカーボン等の導電性材料を混練したものを用いても、プラスチックマスク１２０の摩擦帯電を回避することができる。
【００２９】
また、表面層１０１ｂとしては、導電性材料の中でも、特に金属材料を用いることが望ましい。そうすれば、金属材料からなる表面層１０１ｂによってプラスチックマスク１２０の剛性を高めることができるからである。更には、摩擦帯電の回避を必要としない場合には、表面層に限らず、多層構造における何れかの層に金属材料を用いて剛性を高めてもよい。
【００３０】
また、これまで、印刷版として、複数の貫通開口からなる版パターンを有する孔版を製造する印刷版製造方法について説明したが、複数の凹部からなる版パターンを有する凹版を製造する印刷版製造方法にも、本発明の適用が可能である。
【００３１】
以上、本実施形態に係る印刷版製造方法によれば、レーザー加工装置として、何れも高額なガス漏れ機構が不要なＣＯ_２レーザー装置１やフェムト秒レーザー装置４を用いるので、ガス漏れ防止機構が設けられたレーザー発振器の交換に起因するコストアップを回避することができる。更には、これらＣＯ_２レーザー装置１やフェムト秒レーザー装置４は何れもレーザー光の連続照射が可能なものであるので、断続ショット加工による加工速度の低下に起因するコストアップも回避することができる。しかも、数十μｍといったファインピッチな貫通開口でも十分な内壁平滑性を得ることができる。
【００３２】
また、フォトリソグラフィー法によらずに版パターンを形成するので、現像液やエッチング液を発生させたり、オンデマンド型の生産要求への対応を困難にしたりといった事態を解消することができる。
【００３３】
また、加工対象物たる薄板１０１として、アクリルからなる基層１０１ａを有するものを用いることで、ＣＯ_２レーザー加工処理時のアシストガスの使用を不要にして、その使用によるコストアップを低減することができる。
【００３４】
また、薄板１０１として、基層１０１ａに導電性材料からなる表面層１０１ｂが被覆されたものを用いるので、摩擦帯電によって被印刷体たる電子回路基板に悪影響を及ぼすといった事態を生ずることのないプラスチックマスク１２０を製造することができる。
【００３５】
また、ＣＯ_２レーザーでは加工ができない超ファインピッチパターンＰｂをフェムト秒レーザーによって加工する一方で、ファインピッチパターンＰａをＣＯ_２によって加工することで次のことが可能になる。即ち、両パターンが混在する版パターンを形成することができ、しかも、かかる版パターンをフェムト秒レーザー加工処理だけで形成することによる加工効率の悪化を回避することができる。
【００３６】
【発明の効果】
請求項１、２、３、４又は５の発明によれば、上述した（１）から（３）の事項を何れも実現することができるという優れた効果がある。
特に、請求項２又は３の発明によれば、印刷版の貫通開口や凹部についてより確実に十分な内壁平滑性を得ることができるという優れた効果がある。
また特に、請求項３の発明によれば、ＣＯ_２レーザー加工処理時のアシストガスの使用によるコストアップを低減することができるという優れた効果がある。
また特に、請求項４の発明によれば、摩擦帯電によって被印刷体に悪影響を及ぼすといった事態を生ずることのない印刷版を製造することができるという優れた効果がある。
また特に、請求項５の発明によれば、金属層によって剛性を高めた印刷版を製造することができるという優れた効果がある。
また特に、請求項６の発明によれば、超ファインピッチパターンと、ファインピッチパターンとが混在する版パターンを形成することが可能で、しかも、かかる版パターンをフェムト秒レーザー加工処理だけで形成することによる加工効率の悪化を回避することができるという優れた効果がある。
【図面の簡単な説明】
【図１】実施形態に係る印刷版製造方法に用いるレーザー加工装置の概略構成図。
【図２】同レーザー加工装置のＸＹテーブルの要部を示す側面図。
【図３】同レーザー加工装置によって版パターンが形成されたプラスチックマスクを示す拡大平面図。
【図４】同プラスチックマスクを示す拡大断面図。
【符号の説明】
１ ＣＯ_２レーザー装置
２ ＸＹテーブル
３ メインコントローラ
４ フェムト秒レーザー装置
１０１ 薄板（加工対象物）
１０１ａ 基層
１０１ｂ 表面層
ｃＬ ＣＯ_２レーザー光
ｆＬ フェムト秒レーザー光[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a printing plate manufacturing method for manufacturing a printing plate by forming a plate pattern including a plurality of through openings or concave portions by laser processing on a processing target having at least a base layer mainly composed of plastic. is there.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there has been known a printing method of printing a printing pattern made of a printing material such as ink, an adhesive, a cream solder, and a resin on a printing medium using a printing plate. For example, in the field of bookbinding, a printing method of printing a photographic image pattern or a character image pattern made of ink on paper using a printing plate is widely used. In the field of electronic circuits, for example, a printing method of printing a fine electrode pattern made of cream solder on a circuit board using a printing plate is used.
[0003]
As one of the printing plate manufacturing methods for manufacturing a printing plate on which a printing plate pattern corresponding to a printing pattern is formed, a printing plate pattern including a plurality of through openings and concave portions is formed on a base material such as a metal plate by YAG laser processing. There is. However, in the case of a plate pattern formed by YAG laser processing, it has become difficult to meet recent demands for higher resolution of images and further miniaturization of electronic circuits. In the YAG laser processing, sufficient inner wall smoothness cannot be obtained in a fine through-opening or a concave portion of, for example, several tens [μm] which can meet such a demand, and the printing material is not sufficiently removed from the through-opening to perform printing. This is because it will be defective.
As another printing plate manufacturing method, a method of forming a plate pattern by a photolithography method is also known. According to this method, sufficient inner wall smoothness can be obtained even with the fine through-opening or concave portion as described above. However, there is a problem that a larger amount of waste material is generated as compared with the method using YAG laser processing. There is also a problem that it is difficult to respond to on-demand type production requests such as small lot orders of various types. This is because a developing solution or an etching solution is generated as a waste material, or a photomask having a different light-shielding pattern needs to be prepared according to a plate pattern.
[0005]
Therefore, the present applicant has previously proposed printing plates described in Patent Literature 1 and Patent Literature 2. In these printing plates, a plastic plate is used as a base material. The plate pattern includes a plurality of through-openings and recesses obtained by ablating a plastic material by excimer laser irradiation. In such a printing plate, a plate pattern is formed without using a photolithography method, so that any of the above-mentioned problems caused by the photolithography method can be solved. Moreover, since the ablation phenomenon basically occurs faster than the heat conduction, the situation in which the through-opening or the inner wall of the concave portion is deformed by thermal melting unlike the case of YAG laser processing does not occur. Therefore, sufficient inner wall smoothness can be obtained even with the fine through-opening or concave portion as described above.
[0006]
[Patent Document 1]
Japanese Patent No. 3279761 [Patent Document 2]
JP-A-10-291293
[Problems to be solved by the invention]
However, the present applicant has encountered the following problems in reducing the cost of these printing plates. That is, it is difficult to reduce the cost because an excimer laser oscillator that requires periodic replacement is expensive or an excimer laser device needs to be periodically replenished with expensive krypton fluorine (KrF) gas. It is. Furthermore, in processing by an excimer laser, the laser cannot be continuously oscillated. Therefore, it is necessary to perform intermittent shot processing in which the processing object is repeatedly stopped and moved for each shot of the laser to process a continuous through-opening or a concave portion. Will be greatly affected.
[0008]
The present invention has been made in view of the above background, and an object of the present invention is to provide a printing plate manufacturing method capable of realizing any of the following items.
(1) A plate pattern can be formed without generating a developing solution or an etching solution as in the photolithography method or making it difficult to respond to on-demand type production requirements.
(2) Sufficient inner wall smoothness is obtained even with a fine through-opening or concave portion.
(3) Suppression of cost increase due to periodic replenishment of gas, periodic replacement of laser oscillator, reduction in processing speed due to intermittent shot processing, and the like.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, according to the first aspect of the present invention, a plate pattern including a plurality of through-holes or recesses is formed by laser processing on an object to be processed having at least a base layer mainly composed of plastic for printing. In a printing plate manufacturing method for manufacturing a plate, a CO ₂ laser processing is used as the laser processing, and acrylic, polycarbonate, polyethylene terephthalate, polyethylene, polypropylene, polyamide 6, polyamide 6, polyacetal, polyurethane and polyimide are used as the processing object. Characterized by using a material having the above-described base layer mainly composed of at least one plastic selected from the group consisting of:
According to a second aspect of the present invention, there is provided the printing plate manufacturing method according to the first aspect, wherein the object to be processed has the base layer mainly composed of at least one plastic selected from acryl, polycarbonate, and polyethylene terephthalate. Is used.
According to a third aspect of the present invention, there is provided the printing plate manufacturing method according to the third aspect, wherein the object to be processed has the above-mentioned base layer mainly composed of acryl.
According to a fourth aspect of the present invention, in the printing plate manufacturing method of the first, second or third aspect, as the object to be processed, a material obtained by kneading a plastic material of the base layer with a conductive material is used. It is characterized by using a material coated with a surface layer made of a conductive material.
According to a fifth aspect of the present invention, in the printing plate manufacturing method of the first, second, third, or fourth aspect, the object to be processed is formed by forming a metal layer on the base layer. It is.
According to a sixth aspect of the present invention, in the printing plate manufacturing method according to the first, _{second, third} , fourth, or fifth aspect, the object to be processed is a femtosecond laser in addition to the plate pattern obtained by the CO ₂ laser processing. A plate pattern is formed by processing.
[0010]
The present inventors have completed these inventions based on the intensive research described below. That is, conventionally, it has been considered that the CO ₂ laser processing is not suitable for fine-pitch processing because the inner wall of the through-opening or the concave portion is melted and slightly deformed by heating. However, when the present inventor tried an experiment described later, it was found that a plastic film made of acrylic, polycarbonate (hereinafter, referred to as “PC”) or polyethylene terephthalate (hereinafter, referred to as “PET”) had a fine particle obtained by CO ₂ laser processing. With sufficient through-opening, sufficient inner wall smoothness could be obtained. Gases that require periodic replenishment in a CO ₂ laser oscillator are less expensive than KrF, and the CO ₂ laser oscillator itself is less expensive than an excimer laser oscillator. Further, in the CO ₂ laser device, it is possible to continuously oscillate the CO ₂ laser. Note that the CO ₂ laser uses a processing shape similar to that of acrylic, PC, and PET to polyethylene (hereinafter, referred to as “PE”), polypropylene (hereinafter, referred to as “PP”), polyamide 6 (hereinafter, referred to as “PA6”), and polyacetal ( It is known that it can be obtained from POM), polyurethane (PUR), and polyimide (PI).
[0011]
Accordingly, a plate pattern is formed by CO ₂ laser processing on a workpiece having a base layer containing at least one plastic selected from the group consisting of acrylic, PC, PET, PE, PP, PA6, POM, PUR, and PI. In the printing plate manufacturing method according to any one of the first to fifth aspects, the following is possible. That is, it is possible to suppress an increase in cost due to periodic gas replenishment, periodic replacement of the laser oscillator, a reduction in processing speed due to intermittent shot processing, and the like. In addition, sufficient smoothness of the inner wall can be obtained even with a fine through-opening or concave portion of several tens μm.
Further, since the plate pattern is formed without using the photolithography method, it is possible to eliminate a situation in which a developing solution or an etching solution is generated, and it is difficult to respond to an on-demand type production request.
Therefore, any of the above items (1) to (3) can be realized.
[0012]
In particular, in the printing plate manufacturing method of claim 2 or 3, the main component is at least one plastic selected from acrylic, PC and PETH, which has been confirmed by experiments to obtain sufficient inner wall smoothness. Since the object to be processed having the base layer is used, sufficient inner wall smoothness can be more reliably obtained for the through-opening and the concave portion of the printing plate.
[0013]
In particular, in the printing plate manufacturing method according to the third aspect, it is possible to reduce the cost increase due to the use of the assist gas during the CO ₂ laser processing for the following reason. In other words, the inventors of the present invention have conducted experiments described below, and have found that even for acrylics, even if almost no assist gas for performing processing while covering the CO ₂ laser in a dry atmosphere is used, sufficient inner wall smoothness can be obtained. It was confirmed that a certain through opening could be obtained.
[0014]
In particular, according to the printing plate manufacturing method of the fourth aspect, it is possible to manufacture a printing plate that does not adversely affect a printing medium due to frictional charging. Specifically, a printing plate made of only an insulating material such as a plastic plate may be charged during printing by friction with a printing material printing member such as a squeegee. If the charging potential gradually increases due to repeated friction, a current will eventually flow into the printing medium and exert an adverse effect. On the other hand, the printing plate manufactured by the printing plate manufacturing method of claim 4 imparts conductivity by kneading a conductive material to the plastic material of the base layer or coating the base layer with a surface layer made of the conductive material. As a result, charges can be moved inside the printing plate and released to the outside. For this reason, a situation in which frictional charging adversely affects the printing medium does not occur.
[0015]
In particular, in the printing plate manufacturing method according to the fifth aspect, by using a metal plate formed on a base layer as a processing object, a printing plate having increased rigidity by the metal layer can be manufactured.
[0016]
In particular, in the printing plate manufacturing method according to the sixth aspect, a pattern (hereinafter, referred to as an ultra-fine pitch pattern) having extremely fine through-holes and concave portions, which is difficult to process by CO ₂ laser processing, is slightly larger than that. It is possible to form a plate pattern in which a pattern including through openings and concave portions (hereinafter referred to as a fine pitch pattern) is mixed. In addition, it is possible to avoid the deterioration of the processing efficiency caused by forming such a plate pattern only by the femtosecond laser processing. Specifically, in recent years, it has been found that not only excimer laser processing but also femtosecond laser processing can realize processing of through openings and recesses by ablation. Since the processing is performed by ablation, sufficient inner wall smoothness can be obtained similarly to the excimer laser processing. Furthermore, an expensive gas leakage prevention mechanism is not required because no harmful gas is generated, it is possible to oscillate the femtosecond laser almost continuously, and the laser spot diameter is extremely small, so that extremely fine processing is performed. Is possible. On the other hand, due to the small laser spot diameter, there is a problem that the processing efficiency is deteriorated in a relatively large through-opening or concave portion. In this printing plate manufacturing method, an ultra-fine pitch pattern that is difficult to process by CO ₂ laser processing is formed by femtosecond laser processing, while a fine pitch pattern can be formed by CO ₂ laser processing. By doing so, it is possible to form a plate pattern in which both patterns are mixed, and to avoid a decrease in processing efficiency due to forming the plate pattern only by femtosecond laser processing.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of a printing plate manufacturing method according to the present invention will be described.
First, an experiment performed by the inventor will be described.
[Experiment 1]
Five types of laser processing objects were prepared. Then, using a CO ₂ laser processing apparatus manufactured by Quantum Electronics, a long hole having a width of about 50 [μm] was formed in these processing objects, and the inner wall smoothness was examined. Table 1 below summarizes the structure of the processing target, the processing conditions, and the evaluation results of the inner wall smoothness.
[Table 1]

[0018]
As shown in Table 1, it can be seen that a fine pitch through opening having a width of about 50 [μm] obtained by subjecting acrylic, PC or PET to CO ₂ laser processing exhibits sufficient inner wall smoothness. In addition, as the assist gas at the time of processing, Air having a pressure of 0.5 [kg / cm ² ] was used, but when acrylic was used as a processing target, the same result was obtained even without using the assist gas. Was done.
[0019]
Next, specific contents of the present printing plate manufacturing method will be described.
FIG. 1 is a schematic configuration diagram showing a laser processing apparatus used in the present printing plate manufacturing method. This laser processing device includes a CO ₂ laser device 1, a femtosecond laser device 4, an XY table 2, a main controller 3, and the like. The main controller 3 controls the overall operation of the laser processing apparatus, and is electrically connected to the CO ₂ laser apparatus 1, the femtosecond laser apparatus 4, a table controller 22 described later, and the like.
[0020]
A work 100 is held on the XY table 2. This work 100 has a base plate made of acrylic, a thin plate 101 as a processing object covered with a surface layer made of a conductive material, and a thin plate 101 on a surface opposite to the laser irradiation surface (hereinafter referred to as a back surface). And a fixed frame 102. The XY table 2 holds the work 100 on the work holding table 20 by clipping the frame 102 of the work 100 by a clip mechanism (not shown). The work holding table 20 changes the irradiation point of the laser beam emitted from each laser device on the thin plate 101 by moving in the XY direction. The movement of the work holding table 20 is controlled by the table controller 22 of the XY table 2.
[0021]
The CO ₂ laser device 1 has a CO ₂ laser oscillator 10 and a processing head 11. CO ₂ laser light cL oscillated from CO ₂ laser oscillator 10, via the machining head 11 having such a reflecting mirror and a condensing lens (not shown), is applied to the thin plate 101 of the workpiece 100. At this time, when the assist gas is press-fitted into a gas receiving port (not shown) of the processing head 11, the assist gas is ejected from the processing head 11 together with the CO ₂ laser. By the irradiation of the CO ₂ laser beam cL, a through hole having a diameter of about 50 μm is formed in the thin plate 101. When a long hole having a width of about 50 [μm] is formed instead of the through hole, the workpiece 100 is moved on the XY table 2 while continuously irradiating the CO ₂ laser cL.
[0022]
The femtosecond laser device 4 has a femtosecond laser oscillator 40 and a processing head 41. The femtosecond laser oscillator 40 oscillates a femtosecond laser beam fL having a wavelength in the visible region. The oscillated femtosecond laser light fL is applied to the thin plate 101 of the work 100 via a processing head 41 having an aperture (not shown), an incident mirror, a condenser lens, and the like. The femtosecond laser light fL is a laser output with a pulse emission time of 1 picosecond or less, for example, a laser light wavelength of 775 [nm], a pulse emission time of 150 [femtosecond] or less, and a maximum energy of 800 [μJ / pulse]. ]belongs to. According to this, the energy density of the emitted light reaches a level of several gigawatts in the oscillation pulse, and the temporal energy density is dramatically increased, so that a multiphoton absorption process in which a plurality of photons are simultaneously absorbed occurs. Then, even for a material that has been absorbed only by photons having a large photon energy such as far ultraviolet rays, the energy can be absorbed in the form of simultaneous absorption of a plurality of photons, and an ablation phenomenon can be caused. In addition, since the laser irradiation time is very short, the sublimation ablation process ends before the laser light diffuses inside the workpiece as thermal energy. In addition, since the femtosecond laser light fL has a wavelength in the visible region and is easily visually recognized, it can be used not only for processing but also as optical path guide light for optical axis alignment.
[0023]
FIG. 2 is a side view showing a main part of the XY table 2. In the figure, the XY table 2 is configured such that the work holding table 20 holding the work 100 is moved in the X-axis direction (the depth direction in the figure) with respect to the processing heads (11, 41 in FIG. 1) of each laser device (not shown). It is relatively moved in the Y-axis direction (left-right direction in the figure). Specifically, two legs 23 each having an X groove extending in the depth direction in the drawing are fixed to the lower surface of the work holding table 20. A Y-axis moving table 24 is provided below the work holding table 20 in the figure. Two X guide rails 25 extending in the depth direction in the figure are fixed to the upper surface of the Y-axis moving base 24. The work holding table 20 is supported by the Y-axis moving table 24 by placing the X grooves of the two legs 23 fixed to the lower surface thereof on the rails so as to engage with the X guide rails 25, respectively. You. A linear motor 26 is provided between the work holding table 20 and the Y-axis moving table 24. The linear motor 26 has a lower surface electrode portion 26a fixed to the lower surface of the work holding base 20, and an upper surface electrode portion 26b fixed to the upper surface of the Y-axis moving base 24 so as to face the lower electrode portion 26a. When these electrode portions are excited, an electromagnetic force directed in the X-axis direction in FIG. Thereby, the work holding table 20 moves in the X-axis direction along the X guide rail 25. The Y-axis moving table 24 is supported on a support (not shown), and moves in the Y-axis direction on the support by a mechanism similar to that for moving the work holding table 20 in the X-axis direction. I have.
[0024]
On the upper surface of the X-axis moving base 24, a main projection 27a and a sub-projection 27b extending in the X-axis direction in the figure are provided. A main linear scale 28a and a sub linear scale 28b are fixed to the side surface of the main convex portion 27a and the side surface of the sub convex portion 27b, respectively. These scales have scales (not shown) engraved in the X-axis direction. On the other hand, a main position detection sensor 29a and a sub position detection sensor 29b are fixed to the lower surface of the work holding base 20 so that the scales of the main linear scale 28a and the sub linear scale 28b can be read. As these position detection sensors, for example, reflection type photo sensors can be used. The main position detection sensor 29a outputs an ON / OFF signal obtained by the scale of the main linear scale 28a to the table controller 22. The table controller 22 controls the excitation of the linear motor 26 based on this signal, and relatively moves the work 100 in the X-axis direction with respect to the femtosecond laser beam fL. The sub position detection sensor 29b outputs an ON / OFF signal obtained by the scale of the sub linear scale 28b to the table controller 22 and the main controller (3 in FIG. 1). The main controller controls each laser oscillator (10, 40 in FIG. 1) based on this signal to oscillate each laser. In this laser processing apparatus, in the Y-axis direction, the main position detection sensor and the main linear scale are arranged to face each other, but the sub position detection sensor and the sub linear scale are not provided.
[0025]
The main position detection sensor 29a has a resolution of 1 [μm], and the main linear scale 28a has a scale interval of 0.17 [mm]. On the other hand, a sub-position detection sensor 29b having a resolution of 0.1 [μm] is used, and a sub-linear scale 28b having a scale of 0.5 [μm] at intervals of 0.17 [mm]. Is used. As these linear scales, for example, those manufactured by Renishaw Co., Ltd. can be used. An ON signal emitted from the sub position detection sensor 28b immediately after the ON signal is generated from the main position detection sensor 29a is used as a shot start signal of each laser beam. Then, the next ON signal emitted from the sub position detection sensor 28b is used as a shot stop signal of each laser beam.
[0026]
FIG. 3 is an enlarged plan view showing a plastic mask 120 as a printing stencil on which a plate pattern having a through opening is formed by the laser processing apparatus. The plastic mask 120 is for printing an electrode pattern made of cream solder on an electronic circuit board. In the figure, the plate pattern of the plastic mask 120 includes a fine pitch pattern Pa having a plurality of through openings having a width of about 100 [μm] and an ultra-fine pitch pattern Pb having a plurality of through holes having a width of about 50 [μm]. It is composed of Among these patterns, the fine pitch pattern Pa is one whose area is processed by a CO ₂ laser. The area processing is a processing method in which, for example, when a round hole having a diameter φ is laser-processed, the round hole is punched out at once using a laser spot approximately equal to the diameter φ. On the other hand, since the ultra fine pitch pattern Pb is too small to be processed by the CO ₂ laser, the contour is processed by the femtosecond laser. The contour processing is a processing method in which, for example, when a round hole having a diameter φ is laser-processed, a contour of the round hole is cut out with a laser spot smaller than the diameter φ to obtain a round hole. Laser processing is performed in such a way that a round hole is cut out with a thread saw.
[0027]
FIG. 4 is an enlarged sectional view showing the plastic mask 120. The plastic mask 120 is obtained by forming a plate pattern on the thin plate (101) by laser processing. The thin plate (101) has a base layer 101a made of acrylic and a surface layer 101b made of a conductive material such as metal such as titanium or carbon. In the plastic mask 120 having the plate pattern formed by laser processing on the thin plate (101) having such a configuration, the surface layer 101b made of an electrically conductive material can be used even if it is repeatedly rubbed by a printing material squeezing member such as a squeegee during printing. Charges can be released. Therefore, there is no frictional charging when the printing material is rubbed.
[0028]
It is to be noted that frictional charging of the plastic mask 120 can be avoided even if a material obtained by kneading a conductive material such as carbon is used as the base layer 101a made of plastic instead of providing the surface layer 101b made of a conductive material.
[0029]
Further, as the surface layer 101b, among conductive materials, it is particularly preferable to use a metal material. Then, the rigidity of the plastic mask 120 can be increased by the surface layer 101b made of a metal material. Further, when it is not necessary to avoid frictional charging, the rigidity may be increased by using a metal material for any layer in the multilayer structure, not limited to the surface layer.
[0030]
Also, a printing plate manufacturing method for manufacturing a stencil having a plate pattern including a plurality of through openings has been described above as a printing plate.However, a printing plate manufacturing method for manufacturing an intaglio having a plate pattern including a plurality of recesses has been described. Also, the present invention can be applied.
[0031]
As described above, according to the printing plate manufacturing method according to the present embodiment, the CO ₂ laser device 1 or the femtosecond laser device 4 that does not require an expensive gas leakage mechanism is used as a laser processing device. An increase in cost due to replacement of the provided laser oscillator can be avoided. Further, since both the CO ₂ laser device 1 and the femtosecond laser device 4 can continuously irradiate laser light, it is possible to avoid an increase in cost due to a reduction in processing speed due to intermittent shot processing. . In addition, a sufficient inner wall smoothness can be obtained even with a fine pitch through opening of several tens μm.
[0032]
Further, since the plate pattern is formed without using the photolithography method, it is possible to eliminate a situation in which a developing solution or an etching solution is generated, and it is difficult to respond to an on-demand type production request.
[0033]
In addition, by using a thin plate 101 as an object to be processed having a base layer 101a made of acrylic, the use of an assist gas at the time of CO ₂ laser processing is unnecessary, and the cost increase due to its use can be reduced. .
[0034]
Since the base plate 101a is coated with the surface layer 101b made of a conductive material as the thin plate 101, the plastic mask 120 which does not adversely affect the electronic circuit substrate as a printing medium due to triboelectric charging is used. Can be manufactured.
[0035]
Further, while processing the ultra-fine pitch pattern Pb which cannot be processed by the CO ₂ laser by the femtosecond laser, processing the fine pitch pattern Pa by CO ₂ enables the following. That is, it is possible to form a plate pattern in which both patterns are mixed, and it is possible to avoid a decrease in processing efficiency due to forming such a plate pattern only by femtosecond laser processing.
[0036]
【The invention's effect】
According to the first, second, third, fourth or fifth aspect of the invention, there is an excellent effect that any of the above items (1) to (3) can be realized.
In particular, according to the second or third aspect of the invention, there is an excellent effect that sufficient inner wall smoothness can be more reliably obtained for the through-opening and the concave portion of the printing plate.
In particular, according to the invention of claim 3, there is an excellent effect that the cost increase due to the use of the assist gas during the CO ₂ laser processing can be reduced.
Further, in particular, according to the invention of claim 4, there is an excellent effect that a printing plate can be manufactured without causing a situation in which frictional charging adversely affects a printing medium.
In particular, according to the invention of claim 5, there is an excellent effect that a printing plate having increased rigidity can be manufactured by the metal layer.
In particular, according to the invention of claim 6, it is possible to form a plate pattern in which a super fine pitch pattern and a fine pitch pattern are mixed, and furthermore, such a plate pattern is formed only by femtosecond laser processing. There is an excellent effect that deterioration of the processing efficiency due to the above can be avoided.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a laser processing apparatus used in a printing plate manufacturing method according to an embodiment.
FIG. 2 is a side view showing a main part of an XY table of the laser processing apparatus.
FIG. 3 is an enlarged plan view showing a plastic mask on which a plate pattern is formed by the laser processing apparatus.
FIG. 4 is an enlarged sectional view showing the plastic mask.
[Explanation of symbols]
Reference Signs List 1 CO ₂ laser device 2 XY table 3 Main controller 4 Femtosecond laser device 101 Thin plate (workpiece)
101a Base layer 101b Surface layer cL CO ₂ laser light fL Femtosecond laser light

Claims (6)

In a printing plate manufacturing method for manufacturing a printing plate by forming a plate pattern consisting of a plurality of through openings or recesses by laser processing on a processing target having a base layer containing at least plastic as a main component,
As the laser processing, CO ₂ laser processing is used, and at least one plastic selected from the group consisting of acrylic, polycarbonate, polyethylene terephthalate, polyethylene, polypropylene, polyamide 6, polyacetal, polyurethane, and polyimide is used as the processing object. A method for producing a printing plate, comprising using a substrate having the above base layer as a main component. The printing plate manufacturing method according to claim 1,
A method of manufacturing a printing plate, comprising using, as the object to be processed, an object having the above-mentioned base layer mainly composed of at least one plastic selected from acrylic, polycarbonate and polyethylene terephthalate. The printing plate manufacturing method according to claim 3,
A method of manufacturing a printing plate, characterized in that the object to be processed has the above-mentioned base layer mainly composed of acrylic. The printing plate manufacturing method according to claim 1, 2 or 3,
A method of manufacturing a printing plate, wherein the object to be processed is a material obtained by kneading a plastic material of the base layer with a conductive material, or a material obtained by coating the base layer with a surface layer made of a conductive material. The printing plate manufacturing method according to claim 1, 2, 3, or 4,
A method of manufacturing a printing plate, comprising using, as the processing target, a metal layer formed on the base layer. The printing plate manufacturing method according to claim 1, 2, 3, 4, or 5,
To the workpiece, a printing plate manufacturing method in addition to the plate pattern by the CO ₂ laser processing, and forming a plate pattern by femtosecond laser processing.

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