JP2004190079A - Vacuum treatment apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vacuum treatment apparatus which reduces spherical projections produced on the side of the bottom plate of a base body to be treated, and uniformizes the film thickness and the film quality of a deposited film more. <P>SOLUTION: The vacuum treatment apparatus is provided with a reaction vessel 12 permitting evacuation for subjecting the cylindrical base body 11 to vacuum treatment, a base body holding member 13 for holding the cylindrical base body 11, a gas feed tube 14 for introducing a gaseous starting material into the reaction vessel 12, and a high frequency electrode 15 capable of feeding high frequency electric power exciting the gaseous starting material introduced into the reaction vessel 12 and generating glow discharge. Further, the reaction vessel 12 has a bottom plate 23 provided with an exhaust port 26 for exhausting the inside of the reaction vessel 12 into a vacuum. Then, the distance A between the inside face of the bottom board 23 and the lower end of the cylindrical base body 11 held by the base body holding member 12 satisfies the condition of 70mm≤A≤300mm. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、被処理基体に真空処理を施すための真空処理装置に関し、特に、堆積膜、とりわけ機能性膜、特に半導体デバイスとして用いられる電子写真感光体を形成するための真空処理装置に関する。
【０００２】
【従来技術】
従来、例えば、半導体デバイス、電子写真感光体、画像入力用ラインセンサ、撮影デバイス、光起電力デバイス等を形成するための真空処理方法としては、プラズマＣＶＤ（Ｃｈｅｍｉｃａｌ Ｖａｐｏｒ Ｄｅｐｏｓｉｔｉｏｎ）法、イオンプレーティング法、プラズマエッチング法等、高周波電力により生成されるプラズマを用いた堆積膜形成方法が知られており、そのための装置も数多く実用化されている。
【０００３】
例えば、プラズマＣＶＤ法を用いた堆積膜形成方法、すなわち高周波電力のグロー放電により原料ガスの分解し、その分解種を円筒状基体上に堆積させることによって堆積膜を形成する方法が好適な堆積膜形成手段として実用化されている。この方法を用いた例として、原料ガスにシランガスを用いてアモルファスシリコン（以下、「ａ−Ｓｉ」と記す）薄膜の形成等に利用されており、そのための装置も各種提案されている。
【０００４】
このようなプラズマＣＶＤ法を用いたａ−Ｓｉ薄膜の堆積膜形成装置の一例として、図１４および図１５に、従来の電子写真感光体の製造装置の模式的な構成図を示す。
【０００５】
図１４は、従来の電子写真感光体の製造装置の縦断面を示す模式図であり、図１５は、図１４に示す電子写真感光体の製造装置が備える真空処理装置の横断面を示す模式図である。
【０００６】
図１４および図１５に示すように、従来の電子写真感光体の製造装置は、円筒状基体に真空処理を施すための真空処理装置１０１と、この真空処理装置１０１に原料ガスを供給するためのガス供給装置１０２と、真空処理装置１０１の反応容器１１２内を減圧するための排気装置（不図示）とを備えて構成されている。
【０００７】
真空処理装置１０１の反応容器１１２内には、円筒状基体１１１、支持体加熱用のヒータ１２８、ガス供給管１１４がそれぞれ設けられている。また、反応容器１１２内の中央には、高周波電極１１５が設けられており、この高周波電極１１５に供給する電力を整合するための高周波マッチングボックス１１８が電気的に接続されている。
【０００８】
ガス供給装置１０２は、ＳｉＨ_４などの原料ガスが収容されたボンベ１５１〜１５５、バルブ１６１〜１６５、１７１〜１７５、１８１〜１８５およびマスフローコントローラ１９１〜１９５、圧力調整器１９６〜２００を有して構成されている。各原料ガスの各ボンベ１５１〜１５５は、メインバルブ２０１を介して反応容器１１２内のガス供給管１１４に連通されている。
【０００９】
以上のように構成された従来の電子写真感光体の製造装置を用いて堆積膜を形成する場合には、以下のように行われる。
【００１０】
まず、反応容器１１２内に円筒状基体１１１を設置し、排気装置によって反応容器１１２内を排気配管１２７および排気口１２６を介して排気する。続いて、ヒータ１２８によって、円筒状基体１１１の加熱温度が２０℃〜４５０℃の所定の温度に制御される。
【００１１】
以上のようにして成膜工程の準備が完了した後、以下の手順で各層の成膜を行う。円筒状基体１１１が所定の温度に加熱された後、流出バルブ１８１〜１８５のうちの必要なものおよびメインバルブ２０１を徐々に開き、ガスボンベ１５１〜１５５から所定の原料ガスを、ガス供給管１１４を介して反応容器１１２内に導入する。
【００１２】
次に、マスフローコントローラ１９１〜１９５によって、各原料ガスが所定の流量になるように調整する。このとき、反応容器１１２内の圧力が所定の圧力になるように、メインバルブ２０１の開放状態を調整する。内圧が安定した後、高周波電源１１６から高周波マッチングボックス１１８を経て反応容器１１２内に高周波電力を導入し、グロー放電を生起させ、円筒状基体１１１上に堆積膜が成膜される。
【００１３】
堆積膜が所望の膜厚に成膜された後、高周波電力の供給を止め、流出バルブ１８１〜１８５を閉じて反応容器１１２内へのガスの流入を止め、堆積膜の成膜を終了する。同様の操作を複数回操り返すことによって、所望の多層構造の光受容層を形成することができる。堆積膜の形成中に、回転軸１３６を介して円筒状基体１１１をモータ１３４によって所定の速度で回転させることで、円筒状基体１１１の表面の全周に亘って均一な堆積膜が形成される。
【００１４】
このような電子写真感光体の製造装置により、高品質な堆積膜の形成が行われているが、更なる品質向上のために電子写真感光体の製造装置の改良が進められている。
【００１５】
例えば、従来、ガス供給管に少なくとも２方向に複数のガス放出孔が設けられており、かつガス供給管の長手方向に亘って不均一に設けることで膜厚および膜質の均一化の向上、重合体の飛散によって生じる微小な画像欠陥の改善する技術が開示されている（例えば、特許文献１参照。）。
【００１６】
また、従来、反応容器内に配置された円筒状基体の基体保持部材、ガス供給手段および電力供給手段の各端部を端部被覆部材によって覆うことで、これら端部をグロー放電の領域外に位置させて、プラズマの均一性の向上と微小な画像欠陥の発生を改善する技術が開示されている（例えば、特許文献２参照。）。
【００１７】
【特許文献１】
特開平１１−１７２４５１号公報
【特許文献２】
特開平１１−１９３４７０号公報
【００１８】
【発明が解決しようとする課題】
上述した従来の電子写真感光体の製造装置により、膜厚、膜質の均一化が改善されることで、良好な堆積膜の形成が可能になり、また、歩留の改善による生産性の向上も可能になってきている。しかしながら、製品の高品質化が進む一方で、製品に対する市場の要求が日々高まってきており、更なる高品質な製品を製造可能な電子写真感光体の製造装置および製造方法が求められている。
【００１９】
特に、電子写真感光体においては、電子写真装置の高速化、小型化、低価格化等の要求が非常に高まっており、これらを実現可能な電子写真感光体特性の実現とともに、電子写真感光体の製造時の良品率を向上することが不可欠になっている。さらに、近年、デジタル電子写真装置およびカラー電子写真装置の普及が目覚しく、これら電子写真装置では、文字原稿のみにとどまらず、写真、図等の画像を出力する機会も増加しているため、電子写真装置の高画質化への要求も高まっている。
【００２０】
したがって、このような市場の要求に応えられる製品を製造するためには、従来の電子写真感光体に比較して画像欠陥の個数および大きさともに低減する必要がある。また、画像濃度ムラを低減するためには、比較的大きな面積の円筒状基体上に堆積させる堆積膜の膜厚および膜質の均一性を向上することが必要とされている。さらに、生産性および電子写真感光体特性を向上させるためには、プラズマ処理速度の向上およびプラズマ処理特性の向上が必要とされている。
【００２１】
上述した画像欠陥は、堆積膜が異常成長することで発生した球状突起によって生じる。この球状突起は、プラズマ処理空間内またはプラズマ処理空間を構成する空間形成部材に堆積した重合体や堆積膜が、空間形成部材との応力差によって剥離し、この剥離された膜片が円筒状基体上に飛散することで発生する。このため、従来の電子写真感光体の製造装置では、堆積膜と空間形成部材との密着性等を向上させることによって、球状突起の低減を図っていた。
【００２２】
しかしながら、反応容器内のプラズマの分布は、接地電位近傍で密になることや、反応容器内に導入される原料ガスおよび高周波電力の分布によっても変化してしまう。このため、特に従来の真空処理装置の構成では、底板近傍におけるプラズマの分布に大きな差が生じることや、さらにプラズマの分布が、反応容器内の位置によって異なることによって、プラズマが底板に供給する熱にも分布が発生するため温度差が生じること等から、底板上に堆積する堆積膜の膜厚および膜質等が不均一になり、堆積膜内に応力差が生じるため剥離が生じる。この剥離した膜片が円筒状基体に付着するため、円筒状基体の底板側における球状突起数が増加する場合があった。
【００２３】
さらに、円筒状基体の鉛直方向、すなわち回転軸方向においても、上述した理由により、反応容器内にプラズマの分布が不均一な領域が発生してしまい、この領域内で円筒状基体上に堆積膜を成膜したときに、堆積膜である電子写真感光体の膜厚および膜質が不均一になる場合もあった。
【００２４】
そこで、本発明は、被処理基体の底板側に発生する球状突起を低減させることを可能にし、堆積膜の膜厚および膜質をより一層均一化することができる真空処理装置を提供することを目的とする。
【００２５】
【課題を解決するための手段】
上述した目的を達成するため、本発明は、以下の種々の態様を包含する。
【００２６】
（１） 被処理基体に真空処理を施すための減圧可能な反応容器と、被処理基体を保持するための基体保持部材と、反応容器内に処理用ガスを導入するためのガス導入手段と、反応容器内に導入された処理用ガスを励起してグロー放電を発生させる高周波電力を供給可能な高周波電力供給手段とを備える。また、反応容器は、反応容器内を真空に排気するための排気口が設けられた底板を有する。そして、底板の内面と、基体保持部材に保持された被処理基体の下端との間の距離Ａが、７０ｍｍ≦Ａ≦３００ｍｍの条件を満たす。
【００２７】
以上のように構成された本発明に係る真空処理装置によれば、反応容器を構成する底板の内面から被処理基体の下端を７０ｍｍ以上遠ざけることで、底板上に堆積した不均一な堆積膜に伴う応力差のために、底板上の堆積膜が剥れ、剥離した膜片が被処理基体に飛散することが抑制される。この結果、従来の真空処理装置において困難であった被処理基体の下端部に発生する球状突起を低減することが可能になるとともに、底板の内面近傍に発生してしまう不均一なプラズマ領域内から被処理基体を外すことで、従来の真空処理装置に比較して膜厚および膜質の均一性を向上させることが可能になる。
【００２８】
また、底板と被処理基体の下端との間の距離Ａが大きくなるのに伴って、装置全体が大型化するため、堆積膜を形成するために要する原料ガスの使用量が増加してしまい、装置コストおよび生産コストが嵩んでしまう。したがって、被処理基体の下端部に生じる球状突起の個数、堆積膜の膜厚および膜質の均一性と、装置コストおよび生産コストとを両立する範囲としては、底板と被処理基体の下端との間の距離Ａが３００［ｍｍ］以下に設定される。
【００２９】
なお、本発明において、距離Ａは、底板の内面に直交する方向の距離を指している。
【００３０】
（２） 反応容器は、内壁の少なくとも一部が誘電材料からなる（１）に記載の真空処理装置。これによって、誘電材料からなる内壁からの堆積膜の剥離が激減するため、剥離した膜片が底板上に堆積することも減少する。その結果、底板から堆積膜が剥離した際に、剥離した膜片が被処理基体に飛散することを防止することができるとともに、膜片上に堆積膜が形成されることを抑えることができる。このため、膜片上で異常成長した堆積膜と底板上の堆積膜との応力差による剥離を抑えることが可能になるため、被処理基体の下端部に生じる球状突起を低減させる。また、真空処理装置は、高周波電力を供給するための高周波電極が反応容器の外側に配置されることによって、高周波電極から堆積膜が剥離することを防止できることから底板上に堆積する膜片が更に減少し、そのため被処理基体の下端部に生じる球状突起を更に低減させる。
【００３１】
（３） 反応容器の外側には、高周波電力を供給するための高周波電極が設けられた（１）または（２）に記載の真空処理装置。すなわち、高真空中にＲＦ（Ｒａｄｉｏ Ｆｒｅｑｕｅｎｃｙ）帯近傍からＶＨＦ（Ｖｅｒｙ Ｈｉｇｈ Ｆｒｅｑｕｅｎｃｙ）帯近傍の周波数の高周波電力を高周波電極に供給してプラズマ処理を施すことにより、堆積膜の堆積速度および堆積膜の特性が向上するため、生産性を向上するとともに被処理基体に成膜された堆積膜である感光体の特性を向上することも可能になる。さらに、同一周波数の高周波電力を供給する場合には、定在波によるプラズマの不均一性が生じるが、周波数が異なる複数の高周波電力を反応容器内に同時に供給することにより、複数形成された定在波が同時に供給されることで合成されるため、結果的には明確な定在波が形成されない。したがって、被処理基体近傍のプラズマの均一性が向上され、膜厚および膜質の均一性が更に向上される。
【００３２】
（４） 距離Ａは、９０ｍｍ≦Ａ≦２２０ｍｍの条件を満たす（１）ないし（３）のいずれかに記載の真空処理装置。
【００３３】
（５） 高周波電極に供給する高周波電力は、周波数が、１０ＭＨｚ以上２５０ＭＨｚ以下の範囲内である（３）または（４）に記載の真空処理装置。１０［ＭＨｚ］以上２５０［ＭＨｚ］以下の周波数である高周波電力を用いることで、被処理基体近傍のプラズマの均一性が更に向上される。
【００３４】
さらに、周波数が異なる複数の高周波電力を用いることで、単一の周波数の高周波電力を用いる場合に生じてしまう定在波も抑制できるため、被処理基体近傍のプラズマの均一性が更に向上され、成膜される堆積膜の膜厚および膜質の均一性が向上される。
【００３５】
（６） 反応容器の底板に対向する天板と、基体保持部材に保持された円筒状基体の上端との距離Ｂが２０［ｍｍ］≦Ｂ≦１２０［ｍｍ］の条件を満たす（１）ないし（５）のいずれかに記載の真空処理装置。
【００３６】
（７） 高周波電力は、周波数が異なる複数の高周波電力からなり、周波数範囲内の高周波電力が有する電力値の中で、最も大きい電力値と次に大きい電力値とを有する高周波電力について、周波数が高い方の高周波電力の周波数をｆ１、電力値をＰ１、周波数が低い方の高周波電力の周波数をｆ２、電力値をＰ２とすれば、周波数ｆ１、ｆ２、電力値Ｐ１、Ｐ２が、
ｆ２＜ｆ１
０．１≦Ｐ２／（Ｐ１＋Ｐ２）≦０．９
の条件を満たす（１）ないし（６）のいずれかに記載の真空処理装置。
【００３７】
（８） （１）ないし（７）のいずれかに記載の真空処理装置を用いて、被処理基体に堆積膜を形成する真空処理方法。
【００３８】
（９） 堆積膜が形成された被処理基体は、電子写真感光体である（８）に記載の真空処理方法。
【００３９】
【発明の実施の形態】
本発明は、上述した真空処理装置の構成により、従来の電子写真感光体の製造装置および製造方法における諸問題点を解決し、特に円筒状基体の底板側に発生する球状突起を低減させることで画像欠陥を激減させ、さらに、堆積膜の膜厚および膜質の均一性の向上を可能にするものである。すなわち、反応容器を構成する底板と円筒状基体の下端との距離Ａを、７０［ｍｍ］≦Ａ≦３００［ｍｍ］の条件を満たすようにすることで、底板から剥離した堆積膜の膜片が円筒状基体に飛散することを防止できるため、画像欠陥の原因である球状突起を激減させ、さらに、底板近傍で生じるプラズマの不均一な領域から円筒状基体を外すことで、堆積膜の膜厚および膜質の均一化が可能になる。
【００４０】
以下、本発明の具体的な実施形態の電子写真感光体の製造装置および製造方法について、図面を参照して説明する。
【００４１】
図１に、本発明に適用される電子写真感光体の製造装置が備える真空処理装置の縦断面を示し、図２に、真空処理装置の横断面図を示す。
【００４２】
電子写真感光体の製造装置は、１回のプラズマ処理によって、複数の円筒状基体上に同時に堆積膜を形成することが可能とされており、図１に示すように、円筒状基体にプラズマ処理を施すための真空処理装置１と、この真空処理装置１に原料ガスを供給するためのガス供給装置（不図示）と、真空処理装置１内を減圧するための排気装置（不図示）とを備えて構成されている。
【００４３】
図１および図２に示すように、真空処理装置１は、プラズマ処理によって円筒状基体１１に堆積膜を形成するための反応容器１２と、この反応容器１２内に配置される円筒状基体１１を支持する複数の基体保持部材１３と、反応容器１２内に原料ガスを供給するための複数のガス供給管１４と、高周波放電電力が供給される複数の高周波電極１５と、これら高周波電極１５に高周波電力を供給するための電力供給源１６，１７および整合回路を有するマッチングボックス１８とを備えている。
【００４４】
反応容器１２は、少なくとも一部が誘電材料によって円筒状に形成された側壁２１と、この側壁２１の上端および下端に、天板２２および底板２３がそれぞれ設けられている。反応容器１２内には、側壁２１、天板２２および底板２３によって囲まれた空間をもってプラズマ処理空間２４が構成されている。
【００４５】
底板２３は、基体保持部材１３に保持された円筒状基体１１の下端３１に対して鉛直下方に配置されており、反応容器１２の内壁を構成している。
【００４６】
また、底板２３の略中央部には、プラズマ処理空間２４内に供給された原料ガスを排気するための排気口２６が設けられている。この排気口２６には、排気配管２７の一端が連結されて設けられている。排気配管２７は、他端が、反応容器１２内を減圧するための排気装置に連通されている。
【００４７】
また、反応容器１２内には、この反応容器１２の中心部を取り囲むように、７本の円筒状基体１１が、互いに軸方向が平行になるようにそれぞれ配置される。各円筒状基体１１は、下端３１が基体保持部材１３を介して回転軸３６によって支持されて、上端３２が補助部材１９によって保持されている。基体保持部材１３に保持された各円筒状基体１１は、基体保持部材１３の内部に配設されたヒータ２８によって加熱される。そして、モータ３４を回転駆動することによって、減速ギヤ３５を介して回転軸３６が回転されて、円筒状基体１１は、基体保持部材１３とともに回転軸３６の軸回り方向に回転される。
【００４８】
ガス供給管１４は、棒状に形成されており、原料ガスを反応容器１２内に供給するための複数のガス供給孔（不図示）を有している。ガス供給管は、基端がガス供給管１４に連結されており、このガス供給管１４を介して、原料ガスを供給するガス供給装置に連通されている。そして、原料ガスは、ガス供給装置によって、所定の流量でガス供給管１４を介して供給される。
【００４９】
ガス供給管１４は、形状およびガス供給孔の個数に特に制限はないが、プラズマ処理特性の均一化を図るためには、反応容器１２内のガス濃度分布にむらが生じないように適正化されることが好ましい。また、ガス供給管１４の本数および配置も、製造コスト、取り扱いの面から本数が少ない方が望ましいが、ガス濃度分布にむらが生じないよう対称に配置することが好ましい。
【００５０】
高周波電極１５は、反応容器１２と複数の円筒状基体１１の内面に対して軸方向が平行になるように、反応容器１２の外方に反応容器１２を取り囲むようにしてそれぞれ配置されている。高周波電極１５に供給された高周波電力は、反応容器１２を通して反応容器１２内に供給される。このとき、回転軸３６を通してアース電位に維持された円筒状基体１１および天板２２、底板２３がアノード電極として作用する。
【００５１】
高周波電極１５の本数は、プラズマ処理特性を均一化する効果をより顕著に得るために、図２に示したように円筒状基体１１の本数と同数配置することが好ましい。高周波電極１５の材料としては、導電性を有していればよく、例えばＡｌ、Ｃｒ、Ｍｏ、Ａｕ、Ｉｎ、Ｎｂ、Ｔｅ、Ｖ、Ｔｉ、Ｐｔ、Ｐｄ、Ｆｅ等の金属、およびこれらの合金、例えばステンレス等を使用することができる。
【００５２】
また、反応容器１２の外方には、真空処理装置１の外方に漏洩する電磁波を抑えるための電磁波遮断用シールド３７が、底板２３上に高周波電極１５を取り囲むように配置されている。電磁波遮断用シールド３７は、導電性材料によって円筒状に形成されており、中心軸が円筒状基体１１の配置円の中心を通るように設置されて、一定電位に維持されることで、放出される高周波電力の均一性の向上が図られている。なお、反応容器１２の側壁２１がこのような電磁波遮断用シールドを兼ねるように構成されてもよい。
【００５３】
排気装置は、反応容器１２内を高真空にすることが可能であれば、どのような構成であってもよく、また、ガス供給装置は、堆積膜形成に必要な原料ガスを反応容器１２内に供給可能であれば、どのような構成であってもよい。
【００５４】
次に、本実施形態の真空処理装置１が備える反応容器１２の要部について説明する。図３に、真空処理装置１の要部の縦断面図を示す。
【００５５】
真空処理装置１が備える反応容器１２は、図３に示すように、底板２３の内面と略円筒状の基体保持部材１３上に載置された円筒状基体１１の下端３１との間の距離Ａが、７０［ｍｍ］≦Ａ≦３００［ｍｍ］の範囲内に設定されており、特に９０［ｍｍ］≦Ａ≦２２０［ｍｍ］になるように円筒状基体１１を配置することが好ましい。なお、距離Ａは、底板２３の内面に直交する方向の距離を指している。
【００５６】
円筒状基体１１の下端３１は、底板２３の内面からの距離Ａが７０［ｍｍ］よりも近い場合には、底板２３の内面上に堆積した堆積膜が剥れて生じる膜片等が飛散し、この膜片等が円筒状基体１１の下端部に付着することによって球状突起が激増する。さらに、底板２３と円筒状基体１１の下端３１とを近づけた場合には、プラズマの不均一な領域内に円筒状基体１１の下端部が進入してしまうため、円筒状基体１１の下端部に成膜される堆積膜の膜厚および膜質が変化し、円筒状基体１１の鉛直方向（軸方向）に沿って膜厚ムラおよび膜質ムラが発生してしまう。
【００５７】
したがって、底板２３から円筒状基体１１の下端３１を７０［ｍｍ］以上に遠ざけることで、円筒状基体１１の下端部に発生する球状突起数が減少し、外周面上に成膜された堆積膜の膜厚および膜質ムラが低減される。円筒状基体１１の下端部に発生する球状突起に関しては、底板２３から円筒状基体１１の下端３１を遠ざけるほど減少し、底板２３と円筒状基体１１の下端３１との間の距離Ａを９０［ｍｍ］以上に広げることで、円筒状基体１１の下端部に発生する球状突起をより一層減少させ、堆積膜の膜厚および膜質の均一性が更に向上される。
【００５８】
しかし、底板２３と円筒状基体１１の下端３１との間の距離Ａが大きくなるに伴って、基体保持部材１３の軸方向の長さ（以下、単に基体保持部材１３の長さと称する。）が長くなるため、基体保持部材１３が、反応容器１２内でプラズマの分布が不均一な領域に配置されてしまう。また、基体保持部材１３の長さが長くなることによって、ヒータ２８およびプラズマから供給される熱の鉛直方向における分布が生じて、供給された熱の逃げが低下するため、基体保持部材１３上で温度差が発生してしまう。これにより、基体保持部材１３上に堆積した堆積膜の剥離が生じるために、円筒状基体１１の下部に生じる球状突起の個数が増加してしまう。
【００５９】
さらに、底板２３と円筒状基体１１の下端３１との間の距離Ａが大きくなるのに伴って、装置全体が大型化するため、堆積膜を形成するために要する原料ガスの使用量が増加してしまい、装置コストおよび生産コストが嵩んでしまう。したがって、円筒状基体１１の下端部に生じる球状突起の個数、堆積膜の膜厚および膜質の均一性と、装置コストおよび生産コストとを両立する範囲としては、底板２３と円筒状基体１１の下端３１との間の距離Ａを３００［ｍｍ］以下に設定し、特に２２０［ｍｍ］以下に設定することが好ましい。
【００６０】
基体保持部材１３は、円筒状基体１１の内面側にプラズマが進入することを防止する他に、基体保持部材１３の回転軸３６方向の高さおよび基体保持部材１３と回転軸３６が接する位置等を適宜変更することによって、底板２３から円筒状基体１１の下端３１までの距離を変化させることができるため、本発明においては必須である。しかし、基体保持部材１３の長さに関しては、底板２３と接触することなく回転するためのクリアランスが得られる程度の間隔が確保される必要である。また、基体保持部材１３は、回転軸３６やヒータ２８等の円筒状基体１１および基体保持部材１３の内部に配置されている構成部材に付着する堆積膜を抑制するような長さに設定することが好ましい。
【００６１】
本発明において、反応容器１２を構成する内壁の材質に関しては、特に制限はないが、内壁に堆積した重合体または堆積膜等が剥離することによって生じる膜片等が、底板上に堆積することより、底板から堆積膜等が剥れる際にこれら膜片も同時に飛散したり、また、膜片等の上にさらに堆積膜が形成されることで、正常に堆積した堆積膜との応力差によって堆積膜が剥れたりするため、堆積膜と反応容器を構成する内壁との密着性を向上させることが効果的である。そのために、内壁の少なくとも一部を誘電材料によって形成することが好ましい。誘電性材料としては、例えば、アルミナ、二酸化チタン、窒化アルミニウム、窒化ホウ素、ジルコン、コージェライト、ジルコン−コージェライト、酸化珪素、酸化ベリリウムマイカ系セラミックス等が挙げられる。さらに、反応容器１２の内壁に付着する堆積膜等の密着性をより向上させるためには、反応容器１２を構成する内壁の表面にホーニング処理等が施されたり、内壁に誘電性材料や金属等を被覆すること等によって粗面化されたりしていることが望ましい。
【００６２】
また、反応容器１１を構成する側壁２１は、内径が１４０［ｍｍ］以上７００［ｍｍ］以下にすることが好ましい。内径が１４０［ｍｍ］よりも小さい場合、円筒状基体１１と内壁との間の距離が近づきすぎるために、内壁に堆積した堆積膜が剥離することによって生じた膜片等が円筒状基体１１へ飛散し、球状突起が円筒状基体１１の鉛直方向全体に亘って増加する場合がある。さらに、内壁と円筒状基体１１との間の距離が近づきすぎるために、内壁と円筒状基体１１間でのプラズマの分布が不均一となるため鉛直方向に沿って膜厚および膜質が不均一となってしまう場合がある。逆に、側壁２１の内径が７００［ｍｍ］より大きい場合には、装置全体が大型化し、さらに原料ガスの使用量が増加するため、生産コストおよび装置コストが増加してしまう。
【００６３】
また、高周波電力を供給するための高周波電極１５の配置位置には、特に制限はないが、反応容器１２を構成する側壁２１と同様に、反応容器１２内に高周波電極１５を配置した場合、高周波電極１５の表面に堆積した堆積膜が剥れた際に底板２３に膜片が堆積し、これら膜片が底板２３の剥離を引き起こしたり、底板２３の堆積膜が剥離した際に同時に飛散したりして球状突起の原因となることから、高周波電極１５を反応容器１２の外側に配置する方が好ましい。高周波電極１５の配置は、プラズマ処理特性を均一にするために、同心円状に等間隔に配置することが望ましい。また、高周波電極１５の形状に関して、特に制限はないが、プラズマ処理特性をより一層均一化するために、図１に示したような棒状であることが好ましい。
【００６４】
また、底板２３に対向して設けられた天板２２と円筒状基体１１の上端３２との間の距離Ｂが２０［ｍｍ］≦Ｂ≦１２０［ｍｍ］の範囲内に設定することが好ましい。
【００６５】
接地電位である天板２２近傍でプラズマが密になるため、反応容器１２の鉛直方向に沿ってプラズマの分布が生じてしまう。そのため、反応容器１２を構成する天板２２と円筒状基体１１の上端３２との間の距離Ｂを２０［ｍｍ］以上にすることで、天板２２近傍に発生してしまうプラズマの不均一領域から円筒状基体１１を遠ざけることが可能になる。このため、円筒状基体１１に成膜される堆積膜の膜厚および膜質の均一性が更に向上され、天板２２と円筒状基体１１の上端３２との間の距離Ｂを広げるほど、プラズマがより一層均一な領域で円筒状基体１１上に堆積膜を形成することが可能になる。
【００６６】
しかし、天板２２と円筒状基体１１の上端３２との間の距離Ｂを極端に広げた場合、堆積膜の膜厚および膜質が向上されるが、装置全体が大型化し、堆積膜を形成するために要する原料ガスの使用量が増加してしまい、装置コストおよび生産コストが増大する。したがって、堆積膜の膜厚および膜質の均一性と生産コストとを両立する範囲として、天板２２と円筒状基体１１との間の距離Ｂを１２０［ｍｍ］以下にすることが望ましい。
【００６７】
また、円筒状基体１１の内部にプラズマが進入することを防止し、円筒状基体１１の内面上やヒータ２８等に堆積膜が形成されることを防止するために、円筒状基体１１の上端部を保持するための補助部材１９を配置することが好ましい。
【００６８】
図１に示すように、高周波電力は、周波数が異なる２つの高周波電源１６，１７からそれぞれ供給され、マッチングボックス１８内でそれぞれの整合回路を経て合成され、各高周波電極１５から反応容器１２内に供給される。
【００６９】
本実施形態では、高周波電極１５に供給する高周波電力として、周波数が１０［ＭＨｚ］以上２５０［ＭＨｚ］以下の高周波電力を用いることで、堆積膜の堆積速度および堆積膜の特性が向上されるため、電子写真感光体の生産性および電子写真感光体特性が向上される。さらに、本実施形態では、周波数が異なる複数の高周波電力を高周波電極１５に同時に供給することで、単一の周波数の高周波電力を高周波電極１５に供給する場合に比較して、堆積膜の膜厚および膜質がより一層向上される。本実施形態の真空処理装置１のように、周波数が異なる高周波電力を出力可能な２つの高周波電源を用いる場合、高周波電力の周波数は、堆積速度を向上させる観点から、その下限を１０［ＭＨｚ］以上、好ましくは３０［ＭＨｚ］以上にすることが望ましい。すなわち、周波数が２５０［ＭＨｚ］よりも大きい場合には、電力の進行方向での減衰が顕著になり、異なる周波数の高周波電力との減衰率のずれが顕著になり、十分な均一化効果が得られない。
【００７０】
なお、本実施形態の真空処理装置１では、高周波電力を出力可能な２つの電源を用いているが、本発明においては、高周波電力が供給可能であればよいため、高周波電源の個数に関して制限はない。周波数が異なる複数の高周波電力を高周波電極にそれぞれ供給する際には、少なくとも２つの異なる周波数の高周波電力を同一電極に供給可能な構成であればよい。
【００７１】
反応容器内への複数の高周波電力の供給は、同一の電極から行うことが好ましい。異なる周波数の高周波電力を各々別の電極からそれぞれ供給した場合には、電極ごとに高周波電力の周波数に依存した定在波が生じてしまう。この結果、電極近傍のプラズマ特性は、この定在波に応じた分布形状をもってしまい、生成活性種の種類・比率や、イオンのエネルギーが、反応容器内の位置によって異なってしまうことがある。
【００７２】
電極に供給する複数の高周波電力の関係、すなわち、周波数および電力比率は実際にプラズマ処理特性の均一性を確認しながら決定すればよいが、それぞれの高周波電力における周波数の差があまりにも小さいと、実質的に同一周波数の高周波電力を印加した場合と同等となってしまい、各々の定在波の節位置、腹位置が近いため十分な定在波抑制効果が得られない。また、その差が大きすぎる場合には、周波数が小さい方の高周波電力の高周波電界定在波の波長が、周波数が大きい方の高周波電力の高周波電界定在波の波長に対して大きすぎるために、十分な定在波抑制効果が得られない。
【００７３】
また、高周波電極１５に供給する高周波電力の電力比率に関しては、上述した周波数範囲内において２つの高周波電力を供給する場合、第１の高周波電力をＰ１、これより周波数の低い第２の高周波電力をＰ２としたときに、電力の総和（Ｐ１＋Ｐ２）に対する第２の高周波電力Ｐ２の比率を０．１以上０．９以下の範囲内にすることが好ましい。
【００７４】
第２の高周波電力が電力の総和に対してこの範囲内よりも小さい場合、高周波電界は、第１の高周波電力に起因する成分が支配的となってしまい定在波抑制効果が得られない。一方、第２の高周波電力を大きくするに従って、第２の高周波電力が反応容器１２内での原料ガス分解に及ぼす影響が大きくなり、第２の高周波電力を単独で用いた場合に近似してしまうため、定在波抑制効果が小さくなる。したがって、少なくとも一方の高周波電力が、２つの電力の総和に対して１０％以上にすることが、定在波抑制効果を確実に得るうえで必要である。
【００７５】
以上のように２つの高周波電力を組み合わせた場合に効果が十分に得られるが、さらに第３の高周波電力を組み合わせることも可能である。第３の高周波電力の範囲としては、第１、第２の高周波電力が適切な範囲に設定されている限りにおいては特に制限はないが、以下のようにすることができる。
【００７６】
第３の高周波電力（電力Ｐ３）の周波数ｆ３が、第１および第２の高周波電力の周波数ｆ１、ｆ２と同様に、１０［ＭＨｚ］以上２５０［ＭＨｚ］以下の範囲内にある場合には、第１の高周波電力（Ｐ１、ｆ１）、第２の高周波電力（Ｐ２、ｆ２）を組み合わせた場合と同様の作用が期待できる。このとき、第１〜第３の高周波電力Ｐ１〜Ｐ３の中で、電力値の上位２つを第１および第２の高周波電力Ｐ１、Ｐ２と再定義すれば、第３の高周波電力Ｐ３が最も電力値が低いことになる。この場合には、第３の高周波電力Ｐ３によるマッチング不整合が起こりにくく、且つ第３の高周波電力Ｐ３による定在波抑制効果が加わるため、第１および第２の高周波電力Ｐ１、Ｐ２を組み合わせた場合よりも膜厚および膜質の均一性が更に向上する場合がある。
【００７７】
一方、例えばバイアス効果を得るため、第３の高周波電力の周波数ｆ３を１０［ＭＨｚ］〜２５０［ＭＨｚ］の範囲外に設定する場合にも、ｆ１、ｆ２とＰ１、Ｐ２が本発明の範囲に適切に設定されている限り問題なく使用できる。このように、更なる電力を供給する場合には、その電力を加えることでプラズマ処理特性の均一性が損なわれない程度の電力とする必要がある。
【００７８】
また、真空処理装置１は、円筒状基体１１を反応容器１２の中央を中心とする同一円周上に沿って等間隔に配設することが好ましい。反応容器１２内に円筒状基体１１を均一に配設することによって、反応容器１１内の接地電位が更に均一に配設されるため、反応容器１１内におけるプラズマ分布の均一性が更に向上し、円筒状基体１１に成膜される堆積膜の膜厚および膜質の均一性が向上する。
【００７９】
【実施例】
以下、実施例および比較例により本発明をさらに詳しく説明するが、本発明はこれらにより何ら制限されるものではない。なお、以下の実施例および比較例で用いられる各真空処理装置において、上述した真空処理装置１と同一部材には同一符号を付して説明を省略する。
【００８０】
（実施例１）
図４および図５に示すように、反応容器の高さを変更可能な真空処理装置２を用いて、底板２３と円筒状基体１１（外径８０［ｍｍ］、厚さ３［ｍｍ］、長さ３５８［ｍｍ］の鏡面加工を施した円筒状のアルミニウムシリンダ）の下端３１との間の距離Ａを、７０［ｍｍ］から３００［ｍｍ］まで変更して、円筒状基体１１上に表１に示す条件で、阻止層、光導電層、表面層の順に成膜を行い、電子写真感光体を７本作製した。
【００８１】
真空処理装置２は、反応容器１２の中央に電極５５が配置されている。また、底板２３には、電極５５の下端の外周に沿って複数の排気口５６がそれぞれ設けられている。
【００８２】
高周波電源１６としては、周波数が１０５［ＭＨｚ］である高周波電力を出力可能な電源を用いた。また、電子写真感光体の作製時に用いる各ガスの種類は、各層内で一定の流量とした。但し、円筒状基体１１の上端３２と天板２２との間の距離Ｂは、基体保持部材１３の高さを変更しても、常に４０［ｍｍ］になるように反応容器１２の高さを変更し、原料ガスの流量は反応容器１２内の圧力が表１に示す条件になるように調整した。
【００８３】
【表１】

【００８４】
上述した条件で作製された電子写真感光体について、球状突起数、膜厚ムラ、帯電能ムラおよび感度ムラを下記の条件により測定した。
【００８５】
（球状突起数）
球状突起数の測定では、２［ｍｍ］×２［ｍｍ］の測定範囲内に存在する長径１０［μｍ］以上の大きさの球状突起の個数を測定した。測定位置の表示は、電子写真感光体の長手方向の中央を０［ｍｍ］、中央より上側の位置をプラス（＋）、中央より下側の位置をマイナス（−）とした。電子写真感光体の中央の周方向における任意の点の長手方向の−１６０［ｍｍ］、−１７０［ｍｍ］の位置と、任意の点から周方向に１８０°回転された点における長手方向の−１６０［ｍｍ］、−１７０［ｍｍ］の位置、計４点の位置における球状突起の合計を求めた。同様に７本の電子写真感光体を測定し、７本の球状突起の個数の平均を球状突起数とした。したがって、球状突起の個数が少ないほど、球状突起数が良好であることを示す。
【００８６】
（膜厚ムラ）
膜厚ムラの測定は、電子写真感光体の長手方向の中央を０［ｍｍ］とし、この中央０［ｍｍ］から長手方向に対して上下２０［ｍｍ］間隔で計１７点の膜厚をそれぞれ測定し、測定値の最大値と最小値の差を求め、７本の電子写真感光体の平均を膜厚ムラとした。したがって、膜厚ムラが小さいほど膜厚ムラが良好であることを示す。
【００８７】
（帯電能ムラ）
帯電能ムラの測定は、上述した条件により作製された電子写真感光体を電子写真装置（キヤノン社製：ｉＲ５０００を評価用に改造したもの）にセットして電位特性の評価を行った。その際、プロセススピード２６５［ｍｍ／ｓｅｃ］、前露光量（波長６６０［ｎｍ］のＬＥＤ）４［ｌｕｘ・ｓｅｃ］、帯電器の電流値１０００［μＡ］の条件にて電子写真装置の現像器位置にセットした表面電位計（ＴＲＥＫ社製：Ｍｏｄｅｌ ３４４）の電位センサによって、像露光（波長６５５［ｎｍ］の半導体レーザ）を照射しない状態で感光体の表面電位を測定し、それを帯電能とした。測定位置は、膜厚測定と同一の位置で帯電能を測定し、測定値の最大値と最小値の差を求め、７本の電子写真感光体の平均を帯電能ムラとした。したがって、帯電能ムラが小さいほど帯電能ムラが良好であることを示す。
【００８８】
（感度ムラ）
感度ムラの測定は、上述の条件で表面電位が４００［Ｖ］（暗電位）になるように帯電器の電流値を調整した後、像露光（波長６５５［ｎｍ］の半導体レーザ）を照射し、像露光光源の光量を調整して、表面電位が５０［Ｖ］（明電位）となるようにし、そのときの露光量を感度とした。測定位置は、膜厚測定と同じ位置で感度を測定し、測定値の最大値と最小値の差を求め、７本の電子写真感光体の平均を感度ムラとした。したがって、電子写真感光体の長手方向の感度ムラが小さいほど感度ムラが良好であることを示す。
【００８９】
（比較例１）
底板２３と円筒状基体１１の下端３１との間の距離Ａを５０［ｍｍ］に設定した図４に示した真空処理装置２を用いて、表１に示す条件により実施例１と同様に電子写真感光体を作製した。但し、円筒状基体１１の上端３２と天板２２との間の距離Ｂは、４０［ｍｍ］になるように反応容器１２の高さを調整した。
【００９０】
上述した条件により作製された電子写真感光体について、球状突起数、膜厚ムラ、帯電能ムラおよび感度ムラを実施例１と同様に測定した。
【００９１】
（比較例２）
底板２３と円筒状基体１１の下端３１との間の距離Ａを４００［ｍｍ］に設定した図４および図５に示した真空処理装置２を用いて、表１に示した条件により実施例１と同様に電子写真感光体を作製した。但し、円筒状基体１１の上端３２と天板２２との間の距離Ｂは、４０［ｍｍ］となるように反応容器１２の高さを調整した。
【００９２】
上述した条件により作製された電子写真感光体について、球状突起数、膜厚ムラ、帯電能ムラおよび感度ムラを実施例１と同様に測定した。
【００９３】
実施例１、比較例１および比較例２によって得られた各電子写真感光体について、球状突起数、膜厚ムラ、帯電能ムラおよび感度ムラを、比較例１の各測定値を１００として相対評価を行った。この結果を表２に示す。
【００９４】
【表２】

【００９５】
表２に示すように、底板２３と円筒状基体１１の下端３１との間の距離Ａを変化させた場合、球状突起数は、前記間隔を長くするほど良好になるが、３００［ｍｍ］よりも長くした場合に基体保持部材１３からの剥離が生じるため悪化した。また、帯電能ムラおよび感度ムラについても、球状突起数の影響により３００［ｍｍ］よりも長くした場合に同様に悪化した。膜厚ムラは、底板２３から円筒状基体１１を７０［ｍｍ］以上離間させることで低減され、９０［ｍｍ］以上離間させることでさらに低減された。
【００９６】
以上の結果、底板２３と円筒状基体１１の下端３１との間の距離Ａを７０［ｍｍ］以上３００［ｍｍ］以下の範囲内に設定することによって、球状突起数、膜厚ムラ、帯電能ムラおよび感度ムラが低減され、特に９０［ｍｍ］以上２２０［ｍｍ］以下の範囲内にすることで更に低減された。
【００９７】
（実施例２）
図７に示すように、真空処理装置４は、図４に示した真空処理装置２と基本構成が同一であり、誘電性材料であるアルミナによって側壁６１が形成された反応容器５２を備える装置である。真空処理装置４には、反応容器５２の排気口５６に略Ｌ字状の排気管５７が設けられている。また、図９および図１０に示すように、真空処理装置６は、図７に示した真空処理装置４において、高周波電極１５を反応容器５２の外側に配置した装置である。
【００９８】
真空処理装置４，６を用いて、実施例１と同様にして円筒状基体１１上に表１に示す条件で、阻止層、光導電層、表面層の順に成膜を行い、電子写真感光体を作製した。このとき、高周波電源１６としては、周波数が１０５［ＭＨｚ］である高周波電力を出力可能な電源を用いた。また、電子写真感光体の作製時に用いる各ガスの種類は、各層内で一定の流量とした。但し、底板２３と円筒状基体１１の下端３１との間の距離Ａを９０［ｍｍ］に設定し、円筒状基体１１の上端３２と天板２２との間の距離Ｂを４０［ｍｍ］に設定した。
【００９９】
上述した条件で作製された電子写真感光体について、球状突起数、膜厚ムラ、帯電能ムラおよび感度ムラを実施例１と同様に測定し、実施例１における底板２３と円筒状基体１１の下端３１との間の距離Ａを９０［ｍｍ］に設定して作製された電子写真感光体と相対比較を行った。
【０１００】
実施例２によって得られた電子写真感光体について、球状突起数、膜厚ムラ、帯電能ムラおよび感度ムラを、比較例１の各測定値を１００として相対評価を行った。この結果を表３に示す。
【０１０１】
【表３】

【０１０２】
表３に示すように、反応容器５２を構成する側壁６１を誘電性材料に変更することで、膜厚ムラに変化が現れなかったが、反応容器５２内に生じる膜片等の球状突起の原因となるダストが減少したため、球状突起数が減少した。また、球状突起数が減少したことで、帯電能ムラおよび感度ムラも低減された。次に、高周波電極１５を反応容器５２の外側に配置することで、反応容器５２内のダスト量が更に減少するため、球状突起数が減少し、帯電能ムラおよび感度ムラも低減された。また、反応容器５２の外側に高周波電極１５を配設することで、反応容器５２内への高周波電力の供給がより一層均一化されたため、膜厚ムラが低減された。
【０１０３】
以上の結果、反応容器５２を構成する内壁の少なくとも一部を誘電性材料によって形成することにより、円筒状基体１１上に成膜される堆積膜の膜質が向上し、球状突起数も減少された。さらに、高周波電極１５を反応容器５２の外側に配置することによって、さらに膜厚、膜質が均一になり球状突起数が低減された。
【０１０４】
（実施例３）
図６に示すように、反応容器１２の高さを変更可能な真空処理装置３を用いて、底板２３と円筒状基体１１（外径８０［ｍｍ］、厚さ３［ｍｍ］、長さ３５８［ｍｍ］の鏡面加工を施したアルミニウムシリンダ）の下端３１との間の距離Ａを７０［ｍｍ］から３００［ｍｍ］まで変化させて、円筒状基体１１上に表４に示す条件で、阻止層、光導電層、表面層の順に成膜を行い、電子写真感光体を７本作製した。
【０１０５】
このとき、高周波電源１６としては、周波数が１０５［ＭＨｚ］および６０［ＭＨｚ］である高周波電力を出力可能な電源を用いた。また、電子写真感光体の作製時に用いる各ガスの種類は、各層内で一定の流量とした。但し、円筒状基体１１の上端３２と天板２２との間の距離Ｂは、基体保持部材１３の軸方向の高さを変更したときも、常に４０［ｍｍ］になるように反応容器１２の高さを変更し、原料ガスの流量は反応容器１２内の圧力が、表４に示す条件になるように調整した。
【０１０６】
【表４】

【０１０７】
上述した条件により作製された電子写真感光体について、球状突起数、膜厚ムラ、帯電能ムラおよび感度ムラを実施例１と同様に測定した。
【０１０８】
（比較例３）
図６に示すように、底板２３と円筒状基体１１の下端３１との間の距離Ａを５０［ｍｍ］に設定した真空処理装置３を用いて、表４に示した条件により実施例３と同様に電子写真感光体を作製した。但し、円筒状基体１１の上端３２と天板２２との間の距離Ｂは、４０［ｍｍ］となるように反応容器１２の高さを調整した。
【０１０９】
上述した条件により作製された電子写真感光体について、球状突起数、膜厚ムラ、帯電能ムラおよび感度ムラを実施例１と同様に測定した。
【０１１０】
（比較例４）
底板２３と円筒状基体１１の下端３１との間の距離Ａを４００［ｍｍ］に設定した図６に示した真空処理装置３を用いて、表４に示した条件により実施例３と同様に電子写真感光体を作製した。但し、円筒状基体１１の上端３２と天板２２との間の距離Ｂは、４０［ｍｍ］となるように反応容器１２の高さを調整した。
【０１１１】
上述した条件により作製された電子写真感光体について、球状突起数、膜厚ムラ、帯電能ムラおよび感度ムラを実施例１と同様に測定した。
【０１１２】
実施例３、比較例３および比較例４によって得られた各電子写真感光体について、球状突起数、膜厚ムラ、帯電能ムラおよび感度ムラを、比較例３の各測定値を１００として相対評価を行った。この結果を表５に示す。
【０１１３】
【表５】

【０１１４】
表５に示すように、底板２３と円筒状基体１１の下端３１との間の距離Ａを変化させた場合、球状突起数は、距離Ａを長くするほと良好になるが、３００［ｍｍ］より長くした場合に実施例１と同様に基体保持部材１３からの剥離が生じるため悪化した。また、帯電能ムラおよび感度ムラに関しても、球状突起数の影響により３００［ｍｍ］より長くした場合に同様に悪化した。膜厚ムラは、底板２３から円筒状基体１１の下端３１を７０［ｍｍ］以上離間させることで低減され、９０［ｍｍ］以上離間させることで更に低減された。さらに、複数の周波数の高周波電力を用いることにより、単一の周波数の高周波電力を用いた際に生じる定在波を抑制することが可能になるため、全てにおいて良好となり、特に膜厚ムラおよび球状突起数が低減された。
【０１１５】
以上の結果、複数の高周波電力を用いた場合でも、底板２３と円筒状基体１１の下端３１との間の距離Ａを、７０［ｍｍ］以上３００［ｍｍ］以下の範囲内に設定することによって、球状突起数、膜厚ムラ、帯電能ムラおよび感度ムラが低減され、特に９０［ｍｍ］以上２２０［ｍｍ］以下の範囲内に設定することで更に低減され、その効果は、単一の周波数の高周波電力を用いたときに比較してより一層良好であった。
【０１１６】
（実施例４）
図８に示すように、真空処理装置５は、図６に示した真空処理装置３と基本構成が同一であり、誘電性材料であるアルミナによって側壁６１が形成された反応容器５２を備える装置である。また、図１１に示すように、真空処理装置７は、図８に示した真空処理装置５において、高周波電極１５を反応容器５２の外側に配置した装置である。
【０１１７】
真空処理装置５，７を用いて、実施例３と同様にして円筒状基体１１上に表４に示す条件で、阻止層、光導電層、表面層の順に成膜を行い、電子写真感光体を作製した。このとき、高周波電源としては、周波数が１０５［ＭＨｚ］および６０［ＭＨｚ］である高周波電力を出力可能な電源を用いた。また、電子写真感光体の作製時に用いる各ガスの種類は、各層内で一定の流量とした。但し、底板２３と円筒状基体１１の下端３１との間の距離Ａを９０［ｍｍ］、円筒状基体１１の上端３２と天板２２との間の距離Ｂを４０［ｍｍ］に設定した。
【０１１８】
上述した条件で作製された電子写真感光体について、球状突起数、膜厚ムラ、帯電能ムラおよび感度ムラを実施例１と同様に測定し、実施例１における底板２３と円筒状基体１１の下端との間の距離Ａが９０［ｍｍ］に設定して作製された電子写真感光体と相対比較を行った。
【０１１９】
実施例４によって得られた電子写真感光体について、球状突起数、膜厚ムラ、帯電能ムラおよび感度ムラを、比較例３の各測定値を１００として相対評価を行った。この結果を表６に示す。
【０１２０】
【表６】

【０１２１】
表６に示すように、反応容器５２を構成する側壁６１を誘電性材料に変更することで、反応容器５２内に生じる膜片等の球状突起の原因となるダストが減少したため、球状突起数が減少した。また、球状突起数が減少したことで、帯電能ムラおよび感度ムラも低減された。また、複数の周波数の高周波電力を供給したことにより、膜厚ムラも若干低減された。次に、高周波電極１５を反応容器５２の外側に配置することで、反応容器５２内のダスト量が更に減少するため、球状突起数が減少し、帯電能ムラおよび感度ムラも低減された。また、反応容器５２の外部に高周波電極１５を配設することで、反応容器５２内への高周波電力の供給がより一層均一化されたため、膜厚ムラが低減された。さらに、複数の周波数の高周波電力を用いることにより、単一の周波数の高周波電力を用いた際に生じる定在波を抑制することが可能となるため、全てにおいて良好となり、特に膜厚ムラおよび球状突起数が低減された。
【０１２２】
以上の結果、複数の高周波電力を用いた場合でも、反応容器５２を構成する内壁の少なくとも一部が誘電性材料によって形成されることにより、円筒状基体１１上に成膜される堆積膜の膜質が向上し、球状突起数も低減された。さらに、高周波電極１５を反応容器５２の外側に配置することによって、さらに膜厚、膜質が向上され球状突起数が低減された。
【０１２３】
（実施例５）
図１２および図１３に示すように、反応容器５２の内部と外部に電極６５を具え、反応容器５２の高さを変更可能な真空処理装置８を用いて、底板２３と円筒状基体１１（外径８０［ｍｍ］、厚さ３［ｍｍ］、長さ３５８［ｍｍ］の鏡面加工を施したアルミニウムシリンダ）の下端３１との間の距離Ａを７０［ｍｍ］から３００［ｍｍ］まで変更して、実施例３と同様にして円筒状基体１１上に表４に示した条件で、阻止層、光導電層、表面層の順に成膜を行い、電子写真感光体を作製した。
【０１２４】
このとき、高周波電源１６，１７としては、周波数が１０５［ＭＨｚ］および６０［ＭＨｚ］である高周波電力を出力可能な電源を用いた。また、電子写真感光体の作製時に用いる各ガスの種類は、各層内で一定の流量とした。但し、円筒状基体１１の上端３２と天板２２との間の距離Ｂは、基体保持部材１３の高さを変更した場合であっても、常に４０［ｍｍ］になるように反応容器５２の高さを変更した。また、原料ガスの流量は、反応容器５２内の圧力が表４に示した条件になるように調整した。
【０１２５】
上述した条件で作製された電子写真感光体について、球状突起数、膜厚ムラ、帯電能ムラおよび感度ムラを実施例１と同様に測定した。
【０１２６】
（比較例５）
底板２３と円筒状基体１１の下端３１との間の距離Ａを５０［ｍｍ］に設定した図１２に示した真空処理装置８を用いて、表４に示した条件により実施例３と同様に電子写真感光体を作製した。但し、円筒状基体１１の上端３２と天板２２との間の距離Ｂは、４０［ｍｍ］になるように反応容器５２の高さを調整した。
【０１２７】
上述した条件により作製された電子写真感光体について、球状突起数、膜厚ムラ、帯電能ムラおよび感度ムラを実施例１と同様に測定した。
【０１２８】
（比較例６）
底板２３と円筒状基体１１の下端３１との間の距離Ａを４００［ｍｍ］に設定した図１２に示した真空処理装置８を用いて、表４に示した条件により実施例３と同様に電子写真感光体を作製した。但し、円筒状基体１１の上端３２と天板２２との間の距離Ｂは、４０［ｍｍ］になるように反応容器５２の高さを調整した。
【０１２９】
上述した条件により作製された電子写真感光体について、球状突起数、膜厚ムラ、帯電能ムラおよび感度ムラを実施例１と同様に測定した。
【０１３０】
実施例５、比較例５および比較例６によって得られた各電子写真感光体について、球状突起数、膜厚ムラ、帯電能ムラおよび感度ムラを、比較例５の各測定値を１００として相対評価を行った。この結果を表７に示す。
【０１３１】
【表７】

【０１３２】
表７に示したように、真空処理装置の構成を変更して実施例３と同様な条件で実施した結果、球状突起数は、上述した距離Ａを長くするほど良好になるが、距離Ａを３００［ｍｍ］より大きくしたとき、実施例１および実施例３と同様に、基体保持部材からの剥離が生じるため悪化した。また、帯電能ムラおよび感度ムラに関しても、球状突起数の影響により３００［ｍｍ］より大きくしたときに同様に悪化した。膜厚ムラは、底板２３から円筒状基体１１の下端３１を７０［ｍｍ］以上離間させることで低減され、９０［ｍｍ］以上離間させることで更に低減された。
【０１３３】
以上の結果、真空処理装置の構成を変更した場合においても、底板２３と円筒状基体１１の下端３１との間の距離Ａを、７０［ｍｍ］以上３００［ｍｍ］以下に設定することによって、球状突起数、膜厚ムラ、帯電能ムラおよび感度ムラが低減され、特に９０［ｍｍ］以上２２０［ｍｍ］以下に設定することで更に低減された。
【０１３４】
【発明の効果】
上述したように、本発明に係る真空処理装置によれば、反応容器を構成する底板の内面と被処理基体の下端との間の距離Ａが、７０ｍｍ≦Ａ≦３００ｍｍの条件を満たすことによって、被処理基体に成膜された堆積膜に生じる球状突起を低減することができる。そして、本発明の真空処理装置によれば、真空処理空間内のプラズマが均一な領域で、被処理基体上に堆積膜を成膜することが可能になるため、成膜された堆積膜の膜厚および膜質の均一性を向上し、生産性も向上することができる。
【図面の簡単な説明】
【図１】本発明に係る実施形態の真空処理装置の縦断面図である。
【図２】図１に示す真空処理装置の横断面図である。
【図３】図１に示す真空処理装置が備える反応容器の下部の縦断面図である。
【図４】実施例１、比較例１，２で用いる真空処理装置の縦断面図である。
【図５】図４に示す真空処理装置の横断面図である。
【図６】実施例３、比較例３，４で用いる真空処理装置の縦断面図である。
【図７】実施例２で用いる真空処理装置の縦断面図である。
【図８】実施例４で用いる真空処理装置の縦断面図である。
【図９】実施例２で用いる真空処理装置の縦断面図である。
【図１０】図９に示す真空処理装置の横断面図である。
【図１１】実施例４で用いる真空処理装置の縦断面図である。
【図１２】実施例５、比較例５，６で用いる真空処理装置の縦断面図である。
【図１３】図１２に示す真空処理装置の横断面図である。
【図１４】高周波プラズマＣＶＤ法による従来の電子写真感光体の製造装置の模式図である。
【図１５】図１４に示す電子写真感光体の製造装置が備える真空処理装置の横断面図である。
【符号の説明】
１〜８ 真空処理装置
１１ 円筒状基体
１２ 反応容器
１３ 基体保持部材
１４ ガス供給管
１５ 高周波電極
１６，１７ 電力供給源
１８ マッチングボックス
１９ 補助部材
２１ 側壁
２２ 天板
２３ 底板
２４ プラズマ処理空間
２６ 排気口
２７ 排気配管
２８ ヒータ
３１ 下端
３２ 上端
３４ モータ
３５ 減速ギヤ
３６ 回転軸
３７ 電磁波遮断用シールド
１０１ 真空処理装置
１０２ ガス供給装置
１１１ 円筒状基体
１１２ 反応容器
１１３ 基体保持部材
１１４ ガス供給管
１１５ 高周波電極
１１６，１１７ 電力供給源
１１８ マッチングボックス
１１９ 補助部材
１２１ 側壁
１２２ 天板
１２３ 底板
１２６ 排気口
１２７ 排気配管
１２８ ヒータ
１３４ モータ
１３５ 減速ギヤ
１３６ 回転軸
１９１〜１９５ マスフローコントローラ
１５１〜１５５ 原料ガスボンベ
１６１〜１６５ ボンベバルブ
１７１〜１７５ 流入バルブ
１８１〜１８５ 流出バルブ
１９６〜２００ 圧力調整器
２０１ メインバルブ[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a vacuum processing apparatus for performing vacuum processing on a substrate to be processed, and more particularly, to a vacuum processing apparatus for forming an electrophotographic photosensitive member used as a deposited film, especially a functional film, and particularly a semiconductor device.
[0002]
[Prior art]
Conventionally, for example, as a vacuum processing method for forming a semiconductor device, an electrophotographic photoreceptor, an image input line sensor, a photographing device, a photovoltaic device, and the like, a plasma CVD (Chemical Vapor Deposition) method, an ion plating method, and the like. A method of forming a deposited film using plasma generated by high-frequency power, such as a plasma etching method, is known, and many apparatuses for this purpose have been put to practical use.
[0003]
For example, a deposition film forming method using a plasma CVD method, that is, a method in which a source gas is decomposed by glow discharge of high-frequency power and a decomposed species is deposited on a cylindrical substrate to form a deposited film is preferable. It has been put to practical use as a forming means. As an example using this method, a silane gas is used as a source gas to form an amorphous silicon (hereinafter referred to as “a-Si”) thin film, and various apparatuses have been proposed.
[0004]
As an example of an apparatus for forming a deposited film of an a-Si thin film using such a plasma CVD method, FIGS. 14 and 15 are schematic structural views of a conventional apparatus for manufacturing an electrophotographic photosensitive member.
[0005]
FIG. 14 is a schematic view showing a longitudinal section of a conventional apparatus for manufacturing an electrophotographic photosensitive member, and FIG. 15 is a schematic view showing a cross section of a vacuum processing apparatus provided in the apparatus for manufacturing an electrophotographic photosensitive member shown in FIG. It is.
[0006]
As shown in FIGS. 14 and 15, a conventional apparatus for manufacturing an electrophotographic photosensitive member includes a vacuum processing apparatus 101 for performing vacuum processing on a cylindrical substrate, and a vacuum processing apparatus 101 for supplying a raw material gas to the vacuum processing apparatus 101. The apparatus includes a gas supply device 102 and an exhaust device (not shown) for reducing the pressure inside the reaction vessel 112 of the vacuum processing device 101.
[0007]
In a reaction vessel 112 of the vacuum processing apparatus 101, a cylindrical substrate 111, a heater 128 for heating a support, and a gas supply pipe 114 are provided. A high-frequency electrode 115 is provided at the center of the reaction vessel 112, and a high-frequency matching box 118 for matching power supplied to the high-frequency electrode 115 is electrically connected.
[0008]
The gas supply device 102 is made of SiH ₄ And the like. Gas cylinders 151 to 155 accommodating such raw material gases, valves 161 to 165, 171 to 175, 181 to 185, mass flow controllers 191 to 195, and pressure regulators 196 to 200 are configured. Each cylinder 151 to 155 of each source gas is connected to a gas supply pipe 114 in the reaction vessel 112 via a main valve 201.
[0009]
When a deposited film is formed using the conventional apparatus for manufacturing an electrophotographic photosensitive member configured as described above, the deposition is performed as follows.
[0010]
First, the cylindrical substrate 111 is set in the reaction container 112, and the inside of the reaction container 112 is exhausted by the exhaust device through the exhaust pipe 127 and the exhaust port 126. Subsequently, the heating temperature of the cylindrical substrate 111 is controlled by the heater 128 to a predetermined temperature of 20 ° C to 450 ° C.
[0011]
After the preparation for the film formation process is completed as described above, the film formation of each layer is performed in the following procedure. After the cylindrical base 111 is heated to a predetermined temperature, necessary ones of the outflow valves 181 to 185 and the main valve 201 are gradually opened, and a predetermined raw material gas is supplied from the gas cylinders 151 to 155 to the gas supply pipe 114. Into the reaction vessel 112 via the
[0012]
Next, each of the source gases is adjusted by the mass flow controllers 191 to 195 so as to have a predetermined flow rate. At this time, the open state of the main valve 201 is adjusted so that the pressure in the reaction vessel 112 becomes a predetermined pressure. After the internal pressure is stabilized, high-frequency power is introduced into the reaction vessel 112 from the high-frequency power supply 116 via the high-frequency matching box 118 to generate glow discharge, and a deposited film is formed on the cylindrical substrate 111.
[0013]
After the deposited film is formed to have a desired film thickness, the supply of the high-frequency power is stopped, the outflow valves 181 to 185 are closed, the flow of gas into the reaction vessel 112 is stopped, and the deposition of the deposited film is completed. By repeating the same operation a plurality of times, a light receiving layer having a desired multilayer structure can be formed. During the formation of the deposited film, the cylindrical substrate 111 is rotated at a predetermined speed by the motor 134 via the rotating shaft 136, so that a uniform deposited film is formed over the entire circumference of the surface of the cylindrical substrate 111. .
[0014]
Although a high-quality deposited film is formed by such an electrophotographic photoreceptor manufacturing apparatus, the electrophotographic photoreceptor manufacturing apparatus is being improved to further improve the quality.
[0015]
For example, conventionally, a plurality of gas discharge holes are provided in at least two directions in a gas supply pipe, and the gas supply holes are provided non-uniformly in the longitudinal direction of the gas supply pipe to improve the uniformity of film thickness and film quality. There is disclosed a technique for improving minute image defects caused by scattering of a united structure (for example, see Patent Document 1).
[0016]
Conventionally, each end of a substrate holding member, a gas supply unit, and a power supply unit of a cylindrical base arranged in a reaction vessel is covered with an end covering member, so that these ends are out of a glow discharge region. There is disclosed a technique for improving the uniformity of plasma and reducing the occurrence of minute image defects by positioning them (for example, see Patent Document 2).
[0017]
[Patent Document 1]
JP-A-11-172451
[Patent Document 2]
JP-A-11-193470
[0018]
[Problems to be solved by the invention]
With the above-described conventional electrophotographic photoreceptor manufacturing apparatus, the uniformity of the film thickness and film quality is improved, so that a good deposited film can be formed, and the productivity can be improved by improving the yield. It is becoming possible. However, while the quality of products has been improved, market demands for the products have been increasing day by day, and a manufacturing apparatus and a manufacturing method of an electrophotographic photoreceptor capable of manufacturing higher quality products have been demanded.
[0019]
In particular, in the case of electrophotographic photoreceptors, demands for higher speed, smaller size, lower price, and the like of electrophotographic devices have been greatly increased. It is essential to improve the non-defective rate at the time of manufacturing. Furthermore, in recent years, digital electrophotographic apparatuses and color electrophotographic apparatuses have been remarkably popularized. In these electrophotographic apparatuses, opportunities to output not only text documents but also images such as photographs and drawings have been increasing. There is an increasing demand for higher image quality of the apparatus.
[0020]
Therefore, in order to manufacture a product that meets such market demands, it is necessary to reduce both the number and size of image defects as compared with the conventional electrophotographic photosensitive member. Further, in order to reduce image density unevenness, it is necessary to improve the uniformity of the film thickness and film quality of a deposited film deposited on a cylindrical substrate having a relatively large area. Further, in order to improve the productivity and the characteristics of the electrophotographic photosensitive member, it is necessary to improve the plasma processing speed and the plasma processing characteristics.
[0021]
The above-described image defects are caused by spherical projections generated by abnormal growth of the deposited film. The polymer or deposited film deposited in the plasma processing space or the space forming member constituting the plasma processing space is peeled off due to a stress difference from the space forming member, and the peeled film piece is formed into a cylindrical substrate. Occurs when flying up. For this reason, in a conventional apparatus for manufacturing an electrophotographic photoreceptor, spherical protrusions are reduced by improving the adhesion between the deposited film and the space forming member.
[0022]
However, the distribution of plasma in the reaction vessel changes depending on the density near the ground potential and the distribution of the raw material gas and high-frequency power introduced into the reaction vessel. For this reason, particularly in the configuration of the conventional vacuum processing apparatus, a large difference occurs in the distribution of plasma near the bottom plate, and furthermore, the distribution of plasma differs depending on the position in the reaction vessel, so that the heat supplied to the bottom plate by the plasma is reduced. Therefore, a temperature difference occurs due to the distribution, and the thickness and quality of the deposited film deposited on the bottom plate become non-uniform. A stress difference occurs in the deposited film, thereby causing separation. Since the peeled film pieces adhere to the cylindrical substrate, the number of spherical projections on the bottom plate side of the cylindrical substrate may increase.
[0023]
Further, even in the vertical direction of the cylindrical substrate, that is, in the direction of the rotation axis, a region where the plasma distribution is not uniform occurs in the reaction vessel for the above-described reason, and the deposited film is formed on the cylindrical substrate in this region. In some cases, the film thickness and film quality of the electrophotographic photosensitive member, which is a deposited film, become non-uniform.
[0024]
Therefore, an object of the present invention is to provide a vacuum processing apparatus that enables reduction of spherical protrusions generated on the bottom plate side of a substrate to be processed and that can further uniform the thickness and quality of a deposited film. And
[0025]
[Means for Solving the Problems]
In order to achieve the above-described object, the present invention includes the following various aspects.
[0026]
(1) A reaction vessel capable of reducing the pressure for performing vacuum processing on a substrate to be processed, a substrate holding member for holding the substrate to be processed, gas introducing means for introducing a processing gas into the reaction container, A high-frequency power supply unit capable of supplying high-frequency power for exciting a processing gas introduced into the reaction vessel to generate glow discharge. Further, the reaction vessel has a bottom plate provided with an exhaust port for evacuating the inside of the reaction vessel to a vacuum. Then, the distance A between the inner surface of the bottom plate and the lower end of the substrate to be processed held by the substrate holding member satisfies the condition of 70 mm ≦ A ≦ 300 mm.
[0027]
According to the vacuum processing apparatus of the present invention configured as described above, by moving the lower end of the substrate to be processed at least 70 mm from the inner surface of the bottom plate constituting the reaction vessel, an uneven deposition film deposited on the bottom plate can be formed. Due to the accompanying stress difference, the deposited film on the bottom plate is peeled, and the peeled film pieces are prevented from scattering on the substrate to be processed. As a result, it is possible to reduce the spherical projections generated at the lower end of the substrate to be processed, which were difficult in the conventional vacuum processing apparatus, and to reduce the unevenness of the plasma generated near the inner surface of the bottom plate. By removing the substrate to be processed, it is possible to improve the uniformity of the film thickness and film quality as compared with a conventional vacuum processing apparatus.
[0028]
Further, as the distance A between the bottom plate and the lower end of the substrate to be processed increases, the entire apparatus increases in size, so that the amount of source gas required to form a deposited film increases, Equipment costs and production costs increase. Therefore, the range in which the number of spherical protrusions generated at the lower end of the substrate to be processed, the uniformity of the thickness and quality of the deposited film, and the equipment cost and the production cost are both compatible is the range between the bottom plate and the lower end of the substrate to be processed. Is set to 300 [mm] or less.
[0029]
In the present invention, the distance A indicates a distance in a direction perpendicular to the inner surface of the bottom plate.
[0030]
(2) The vacuum processing apparatus according to (1), wherein at least a part of the inner wall of the reaction vessel is made of a dielectric material. Thereby, the peeling of the deposited film from the inner wall made of the dielectric material is drastically reduced, and the deposition of the peeled film pieces on the bottom plate is also reduced. As a result, when the deposited film is peeled from the bottom plate, the peeled film piece can be prevented from scattering on the substrate to be processed, and the formation of the deposited film on the film piece can be suppressed. For this reason, it is possible to suppress separation due to a stress difference between the deposited film abnormally grown on the film piece and the deposited film on the bottom plate, so that spherical projections generated at the lower end of the substrate to be processed are reduced. Further, in the vacuum processing apparatus, since a high-frequency electrode for supplying high-frequency power is arranged outside the reaction vessel, it is possible to prevent a deposited film from peeling off from the high-frequency electrode, so that a piece of film deposited on the bottom plate is further increased. The spherical projections generated at the lower end of the substrate to be processed are further reduced.
[0031]
(3) The vacuum processing apparatus according to (1) or (2), wherein a high-frequency electrode for supplying high-frequency power is provided outside the reaction vessel. That is, high frequency power of a frequency in the vicinity of the RF (Radio Frequency) band to a frequency in the vicinity of the VHF (Very High Frequency) band is supplied to the high frequency electrode in a high vacuum to perform plasma processing, thereby performing a deposition rate of the deposited film and a deposition rate of the deposited film. Since the characteristics are improved, the productivity can be improved, and the characteristics of the photoreceptor, which is a deposited film formed on the substrate to be processed, can be improved. Furthermore, when high-frequency power of the same frequency is supplied, non-uniformity of plasma due to a standing wave occurs. However, by supplying a plurality of high-frequency powers having different frequencies simultaneously into the reaction vessel, a plurality of formed high-frequency powers are formed. Since standing waves are simultaneously supplied and combined, a clear standing wave is not formed as a result. Therefore, the uniformity of the plasma near the substrate to be processed is improved, and the uniformity of the film thickness and film quality is further improved.
[0032]
(4) The vacuum processing apparatus according to any one of (1) to (3), wherein the distance A satisfies the condition of 90 mm ≦ A ≦ 220 mm.
[0033]
(5) The vacuum processing apparatus according to (3) or (4), wherein the high-frequency power supplied to the high-frequency electrode has a frequency in a range of 10 MHz to 250 MHz. By using high-frequency power having a frequency of 10 [MHz] or more and 250 [MHz] or less, the uniformity of plasma near the substrate to be processed is further improved.
[0034]
Furthermore, by using a plurality of high-frequency powers having different frequencies, a standing wave generated when using a single-frequency high-frequency power can also be suppressed, so that the uniformity of the plasma near the substrate to be processed is further improved, The uniformity of the film thickness and film quality of the deposited film to be formed is improved.
[0035]
(6) The distance B between the top plate facing the bottom plate of the reaction vessel and the upper end of the cylindrical base held by the base holding member satisfies the condition of 20 [mm] ≦ B ≦ 120 [mm] (1) to (1). The vacuum processing apparatus according to any one of (5).
[0036]
(7) The high-frequency power is composed of a plurality of high-frequency powers having different frequencies, and the high-frequency power having the largest power value and the next largest power value among the power values of the high-frequency power within the frequency range has the frequency If the frequency of the higher frequency power is f1, the power value is P1, and the frequency of the lower frequency power is f2 and the power value is P2, the frequencies f1, f2 and the power values P1, P2 are
f2 <f1
0.1 ≦ P2 / (P1 + P2) ≦ 0.9
The vacuum processing apparatus according to any one of (1) to (6), which satisfies the following condition:
[0037]
(8) A vacuum processing method for forming a deposited film on a substrate to be processed using the vacuum processing apparatus according to any one of (1) to (7).
[0038]
(9) The vacuum processing method according to (8), wherein the substrate on which the deposited film is formed is an electrophotographic photosensitive member.
[0039]
BEST MODE FOR CARRYING OUT THE INVENTION
The present invention solves various problems in the conventional electrophotographic photoreceptor manufacturing apparatus and manufacturing method by the configuration of the above-described vacuum processing apparatus, and in particular, reduces spherical projections generated on the bottom plate side of the cylindrical substrate. It is intended to drastically reduce image defects and to improve the uniformity of the thickness and quality of the deposited film. That is, by setting the distance A between the bottom plate constituting the reaction vessel and the lower end of the cylindrical substrate to satisfy the condition of 70 [mm] ≦ A ≦ 300 [mm], the film piece of the deposited film separated from the bottom plate Can be prevented from scattering on the cylindrical substrate, the spherical projections that cause image defects are drastically reduced, and furthermore, the cylindrical substrate is removed from the non-uniform region of the plasma generated near the bottom plate, whereby the film of the deposited film is formed. The thickness and film quality can be made uniform.
[0040]
Hereinafter, a manufacturing apparatus and a manufacturing method of an electrophotographic photosensitive member according to specific embodiments of the present invention will be described with reference to the drawings.
[0041]
FIG. 1 shows a longitudinal section of a vacuum processing apparatus provided in an apparatus for manufacturing an electrophotographic photosensitive member applied to the present invention, and FIG. 2 shows a cross-sectional view of the vacuum processing apparatus.
[0042]
The apparatus for manufacturing an electrophotographic photoreceptor is capable of simultaneously forming a deposited film on a plurality of cylindrical substrates by one plasma process. As shown in FIG. A vacuum processing apparatus 1 for performing vacuum processing, a gas supply apparatus (not shown) for supplying a raw material gas to the vacuum processing apparatus 1, and an exhaust apparatus (not shown) for reducing the pressure inside the vacuum processing apparatus 1 It is provided with.
[0043]
As shown in FIGS. 1 and 2, the vacuum processing apparatus 1 includes a reaction container 12 for forming a deposited film on a cylindrical substrate 11 by plasma processing, and a cylindrical substrate 11 arranged in the reaction container 12. A plurality of base holding members 13 to be supported, a plurality of gas supply pipes 14 for supplying a raw material gas into the reaction vessel 12, a plurality of high-frequency electrodes 15 to which high-frequency discharge power is supplied, Power supply sources 16 and 17 for supplying power and a matching box 18 having a matching circuit are provided.
[0044]
The reaction vessel 12 has a side wall 21 formed at least in part by a dielectric material in a cylindrical shape, and a top plate 22 and a bottom plate 23 at the upper and lower ends of the side wall 21, respectively. In the reaction vessel 12, a plasma processing space 24 is defined by a space surrounded by the side wall 21, the top plate 22, and the bottom plate 23.
[0045]
The bottom plate 23 is disposed vertically below the lower end 31 of the cylindrical base 11 held by the base holding member 13, and forms an inner wall of the reaction vessel 12.
[0046]
An exhaust port 26 for exhausting the source gas supplied into the plasma processing space 24 is provided at a substantially central portion of the bottom plate 23. One end of an exhaust pipe 27 is connected to the exhaust port 26. The other end of the exhaust pipe 27 is connected to an exhaust device for reducing the pressure inside the reaction vessel 12.
[0047]
In the reaction vessel 12, seven cylindrical substrates 11 are arranged so as to surround the center of the reaction vessel 12 so that the axial directions thereof are parallel to each other. The lower end 31 of each cylindrical base 11 is supported by the rotating shaft 36 via the base holding member 13, and the upper end 32 is held by the auxiliary member 19. Each cylindrical substrate 11 held by the substrate holding member 13 is heated by a heater 28 disposed inside the substrate holding member 13. When the motor 34 is driven to rotate, the rotation shaft 36 is rotated via the reduction gear 35, and the cylindrical base 11 is rotated together with the base holding member 13 in the direction around the rotation shaft 36.
[0048]
The gas supply pipe 14 is formed in a rod shape and has a plurality of gas supply holes (not shown) for supplying a source gas into the reaction vessel 12. The base end of the gas supply pipe is connected to the gas supply pipe 14, and the gas supply pipe is connected to a gas supply device that supplies the source gas through the gas supply pipe 14. The source gas is supplied by the gas supply device at a predetermined flow rate through the gas supply pipe 14.
[0049]
The shape of the gas supply pipe 14 and the number of gas supply holes are not particularly limited. However, in order to achieve uniform plasma processing characteristics, the gas supply pipe 14 is optimized so that the gas concentration distribution in the reaction vessel 12 does not become uneven. Preferably. Also, the number and arrangement of the gas supply pipes 14 are desirably small in terms of manufacturing cost and handling, but are preferably arranged symmetrically so as to prevent unevenness in the gas concentration distribution.
[0050]
The high-frequency electrode 15 is arranged outside the reaction vessel 12 so as to surround the reaction vessel 12 such that the axial direction is parallel to the inner surfaces of the reaction vessel 12 and the plurality of cylindrical substrates 11. The high-frequency power supplied to the high-frequency electrode 15 is supplied into the reaction vessel 12 through the reaction vessel 12. At this time, the cylindrical substrate 11, the top plate 22, and the bottom plate 23 maintained at the ground potential through the rotating shaft 36 function as anode electrodes.
[0051]
The number of the high-frequency electrodes 15 is preferably the same as the number of the cylindrical substrates 11 as shown in FIG. 2 in order to obtain a more remarkable effect of making the plasma processing characteristics uniform. The material of the high-frequency electrode 15 may be any material as long as it has conductivity, for example, metals such as Al, Cr, Mo, Au, In, Nb, Te, V, Ti, Pt, Pd, and Fe, and alloys thereof. For example, stainless steel or the like can be used.
[0052]
Outside the reaction vessel 12, an electromagnetic wave shielding shield 37 for suppressing electromagnetic waves leaking outside the vacuum processing apparatus 1 is arranged on the bottom plate 23 so as to surround the high-frequency electrode 15. The electromagnetic wave shielding shield 37 is formed in a cylindrical shape by using a conductive material, is installed so that a central axis thereof passes through the center of an arrangement circle of the cylindrical substrate 11, and is emitted by being maintained at a constant potential. The high-frequency power uniformity is improved. Note that the side wall 21 of the reaction vessel 12 may be configured to also serve as such an electromagnetic wave shielding shield.
[0053]
The exhaust device may have any configuration as long as the inside of the reaction container 12 can be made to have a high vacuum. The gas supply device supplies the source gas necessary for forming a deposited film to the inside of the reaction container 12. Any configuration may be used as long as it can be supplied.
[0054]
Next, a main part of the reaction vessel 12 provided in the vacuum processing apparatus 1 of the present embodiment will be described. FIG. 3 shows a longitudinal sectional view of a main part of the vacuum processing apparatus 1.
[0055]
As shown in FIG. 3, the reaction vessel 12 provided in the vacuum processing apparatus 1 has a distance A between the inner surface of the bottom plate 23 and the lower end 31 of the cylindrical substrate 11 placed on the substantially cylindrical substrate holding member 13. Is set in the range of 70 [mm] ≦ A ≦ 300 [mm], and it is particularly preferable to arrange the cylindrical base body 11 so that 90 [mm] ≦ A ≦ 220 [mm]. The distance A indicates a distance in a direction orthogonal to the inner surface of the bottom plate 23.
[0056]
When the distance A from the inner surface of the bottom plate 23 is less than 70 [mm], the lower end 31 of the cylindrical substrate 11 scatters film fragments and the like generated by peeling off the deposited film deposited on the inner surface of the bottom plate 23. When this film piece or the like adheres to the lower end of the cylindrical substrate 11, the number of spherical projections increases sharply. Further, when the bottom plate 23 and the lower end 31 of the cylindrical base 11 are brought close to each other, the lower end of the cylindrical base 11 enters into a non-uniform region of the plasma. The film thickness and film quality of the deposited film to be formed change, and the film thickness unevenness and the film quality unevenness occur along the vertical direction (axial direction) of the cylindrical substrate 11.
[0057]
Therefore, by moving the lower end 31 of the cylindrical base 11 away from the bottom plate 23 by 70 mm or more, the number of spherical protrusions generated at the lower end of the cylindrical base 11 is reduced, and the deposited film formed on the outer peripheral surface is reduced. Of the film thickness and film quality are reduced. The spherical protrusion generated at the lower end of the cylindrical base 11 decreases as the lower end 31 of the cylindrical base 11 is further away from the bottom plate 23, and the distance A between the bottom plate 23 and the lower end 31 of the cylindrical base 11 is 90 [ mm] or more, the spherical projections generated at the lower end of the cylindrical substrate 11 are further reduced, and the uniformity of the thickness and quality of the deposited film is further improved.
[0058]
However, as the distance A between the bottom plate 23 and the lower end 31 of the cylindrical base 11 increases, the axial length of the base holding member 13 (hereinafter, simply referred to as the length of the base holding member 13). Because of the length, the substrate holding member 13 is disposed in a region where the distribution of plasma is uneven in the reaction vessel 12. Further, as the length of the base holding member 13 increases, the distribution of heat supplied from the heater 28 and the plasma in the vertical direction occurs, and the escape of the supplied heat is reduced. A temperature difference occurs. As a result, the deposited film deposited on the substrate holding member 13 is peeled off, so that the number of spherical projections generated at the lower portion of the cylindrical substrate 11 increases.
[0059]
Further, as the distance A between the bottom plate 23 and the lower end 31 of the cylindrical substrate 11 increases, the size of the entire apparatus increases, so that the amount of source gas used to form the deposited film increases. As a result, the equipment cost and the production cost increase. Therefore, the range in which the number of spherical projections generated at the lower end portion of the cylindrical base 11, the uniformity of the film thickness and the film quality of the deposited film, and the equipment cost and the production cost are compatible is limited to the bottom plate 23 and the lower end of the cylindrical base 11. It is preferable that the distance A with respect to 31 be set to 300 [mm] or less, and particularly set to 220 [mm] or less.
[0060]
The base holding member 13 prevents the plasma from entering the inner surface side of the cylindrical base 11, as well as the height of the base holding member 13 in the direction of the rotation axis 36 and the position where the base holding member 13 contacts the rotation shaft 36. The distance from the bottom plate 23 to the lower end 31 of the cylindrical substrate 11 can be changed by appropriately changing the distance, which is essential in the present invention. However, with respect to the length of the base holding member 13, it is necessary to secure an interval such that a clearance for rotating without contacting the bottom plate 23 is obtained. The length of the base holding member 13 is set to a length that suppresses a deposited film that adheres to the cylindrical base 11 such as the rotating shaft 36 and the heater 28 and components disposed inside the base holding member 13. Is preferred.
[0061]
In the present invention, the material of the inner wall constituting the reaction vessel 12 is not particularly limited, but a film piece or the like generated by peeling off the polymer or the deposited film or the like deposited on the inner wall is deposited on the bottom plate. When the deposited film is peeled off from the bottom plate, these film fragments are also scattered at the same time, and the deposited film is further formed on the film fragment, etc., and the deposited film is deposited due to the stress difference from the normally deposited deposited film. Since the film is peeled off, it is effective to improve the adhesion between the deposited film and the inner wall constituting the reaction vessel. Therefore, it is preferable that at least a part of the inner wall is formed of a dielectric material. Examples of the dielectric material include alumina, titanium dioxide, aluminum nitride, boron nitride, zircon, cordierite, zircon-cordierite, silicon oxide, and beryllium mica-based ceramics. Further, in order to further improve the adhesion of the deposited film and the like adhering to the inner wall of the reaction vessel 12, a honing treatment or the like may be applied to the surface of the inner wall constituting the reaction vessel 12, or a dielectric material, metal, or the like may be applied to the inner wall. It is desirable that the surface is roughened by coating.
[0062]
Further, it is preferable that the inner diameter of the side wall 21 constituting the reaction vessel 11 be 140 mm or more and 700 mm or less. When the inner diameter is smaller than 140 [mm], the distance between the cylindrical substrate 11 and the inner wall is too short, and a piece of film or the like generated by the separation of the deposited film deposited on the inner wall is transferred to the cylindrical substrate 11. In some cases, the spherical projections may scatter and increase over the entire vertical direction of the cylindrical substrate 11. Further, since the distance between the inner wall and the cylindrical substrate 11 is too close, the distribution of plasma between the inner wall and the cylindrical substrate 11 becomes uneven, so that the film thickness and the film quality are not uniform along the vertical direction. It may be. Conversely, if the inner diameter of the side wall 21 is larger than 700 [mm], the entire apparatus becomes large, and the amount of used raw material gas increases, so that the production cost and the apparatus cost increase.
[0063]
The position of the high-frequency electrode 15 for supplying the high-frequency power is not particularly limited. However, when the high-frequency electrode 15 is disposed in the reaction vessel 12 like the side wall 21 forming the reaction vessel 12, When the deposited film deposited on the surface of the electrode 15 is peeled off, film fragments are deposited on the bottom plate 23, and these film fragments cause peeling of the bottom plate 23, or scatter at the same time when the deposited film on the bottom plate 23 peels off. Therefore, it is preferable to dispose the high-frequency electrode 15 outside the reaction vessel 12 because it causes spherical projections. The high-frequency electrodes 15 are preferably arranged concentrically at equal intervals in order to make the plasma processing characteristics uniform. Further, the shape of the high-frequency electrode 15 is not particularly limited, but is preferably a rod shape as shown in FIG. 1 in order to further uniform the plasma processing characteristics.
[0064]
Further, it is preferable that the distance B between the top plate 22 provided to face the bottom plate 23 and the upper end 32 of the cylindrical base 11 be set in a range of 20 [mm] ≦ B ≦ 120 [mm].
[0065]
Since the plasma becomes dense near the top plate 22 at the ground potential, the plasma distribution occurs along the vertical direction of the reaction vessel 12. Therefore, by setting the distance B between the top plate 22 constituting the reaction vessel 12 and the upper end 32 of the cylindrical substrate 11 to 20 mm or more, the non-uniform region of plasma generated near the top plate 22 It is possible to keep the cylindrical substrate 11 away from the substrate. For this reason, the uniformity of the film thickness and film quality of the deposited film formed on the cylindrical substrate 11 is further improved, and the plasma increases as the distance B between the top plate 22 and the upper end 32 of the cylindrical substrate 11 increases. It is possible to form a deposited film on the cylindrical substrate 11 in a more uniform area.
[0066]
However, when the distance B between the top plate 22 and the upper end 32 of the cylindrical substrate 11 is extremely widened, the thickness and quality of the deposited film are improved, but the entire apparatus becomes large and the deposited film is formed. As a result, the amount of raw material gas required increases, and the equipment cost and production cost increase. Therefore, the distance B between the top plate 22 and the cylindrical substrate 11 is desirably 120 [mm] or less as a range in which the uniformity of the thickness and quality of the deposited film and the production cost are compatible.
[0067]
Further, in order to prevent plasma from entering the inside of the cylindrical substrate 11 and prevent a deposition film from being formed on the inner surface of the cylindrical substrate 11 or on the heater 28 or the like, the upper end of the cylindrical substrate 11 is formed. It is preferable to dispose an auxiliary member 19 for holding.
[0068]
As shown in FIG. 1, high-frequency power is supplied from two high-frequency power supplies 16 and 17 having different frequencies, is synthesized through respective matching circuits in a matching box 18, and is supplied from each high-frequency electrode 15 into the reaction vessel 12. Supplied.
[0069]
In this embodiment, since the high-frequency power supplied to the high-frequency electrode 15 has a frequency of 10 MHz to 250 MHz, the deposition rate of the deposited film and the characteristics of the deposited film are improved. Further, the productivity of the electrophotographic photosensitive member and the characteristics of the electrophotographic photosensitive member are improved. Further, in the present embodiment, by supplying a plurality of high-frequency powers having different frequencies to the high-frequency electrode 15 at the same time, the thickness of the deposited film is compared with a case where a single-frequency high-frequency power is supplied to the high-frequency electrode 15. And the film quality is further improved. When two high-frequency power supplies capable of outputting high-frequency powers having different frequencies are used as in the vacuum processing apparatus 1 of the present embodiment, the lower limit of the frequency of the high-frequency power is set to 10 [MHz] from the viewpoint of improving the deposition rate. It is desirable that the frequency be 30 MHz or more. That is, when the frequency is higher than 250 [MHz], the attenuation in the traveling direction of the power becomes remarkable, and the difference in the attenuation rate with the high frequency power of a different frequency becomes remarkable, and a sufficient uniformizing effect is obtained. I can't.
[0070]
Note that, in the vacuum processing apparatus 1 of the present embodiment, two power supplies capable of outputting high-frequency power are used. However, in the present invention, it is sufficient that high-frequency power can be supplied. Absent. When supplying a plurality of high-frequency powers having different frequencies to the high-frequency electrode, any configuration may be used as long as at least two high-frequency powers having different frequencies can be supplied to the same electrode.
[0071]
The supply of a plurality of high-frequency powers into the reaction vessel is preferably performed from the same electrode. When high-frequency powers of different frequencies are supplied from different electrodes, a standing wave depending on the frequency of the high-frequency power is generated for each electrode. As a result, the plasma characteristics in the vicinity of the electrode have a distribution shape corresponding to the standing wave, and the type and ratio of generated active species and the energy of ions may differ depending on the position in the reaction vessel.
[0072]
The relationship between a plurality of high-frequency powers supplied to the electrodes, that is, the frequency and the power ratio may be determined while actually confirming the uniformity of the plasma processing characteristics, but if the frequency difference between the respective high-frequency powers is too small, This is equivalent to a case where high-frequency power of substantially the same frequency is applied, and a sufficient standing wave suppression effect cannot be obtained because the nodal position and antinode position of each standing wave are close. If the difference is too large, the wavelength of the high-frequency electric field standing wave of the higher frequency power having the lower frequency is too large relative to the wavelength of the high frequency electric field standing wave of the higher frequency power having the higher frequency. , A sufficient standing wave suppressing effect cannot be obtained.
[0073]
Regarding the power ratio of the high-frequency power supplied to the high-frequency electrode 15, when two high-frequency powers are supplied within the above-mentioned frequency range, the first high-frequency power is P1, and the second high-frequency power having a lower frequency is P1. When P2 is set, the ratio of the second high-frequency power P2 to the total power (P1 + P2) is preferably in the range of 0.1 to 0.9.
[0074]
When the second high-frequency power is smaller than this range with respect to the total power, the high-frequency electric field has a dominant component due to the first high-frequency power, and a standing wave suppressing effect cannot be obtained. On the other hand, as the second high-frequency power is increased, the influence of the second high-frequency power on the decomposition of the raw material gas in the reaction vessel 12 increases, and the second high-frequency power approximates the case where the second high-frequency power is used alone. Therefore, the standing wave suppressing effect is reduced. Therefore, it is necessary for at least one of the high-frequency powers to be 10% or more of the sum of the two powers in order to reliably obtain the standing wave suppression effect.
[0075]
As described above, the effect is sufficiently obtained when two high frequency powers are combined, but it is also possible to combine the third high frequency power. The range of the third high-frequency power is not particularly limited as long as the first and second high-frequency powers are set in appropriate ranges, but can be as follows.
[0076]
When the frequency f3 of the third high frequency power (power P3) is in the range of 10 [MHz] to 250 [MHz], like the frequencies f1 and f2 of the first and second high frequency powers, The same operation as when the first high-frequency power (P1, f1) and the second high-frequency power (P2, f2) are combined can be expected. At this time, if the upper two power values of the first to third high-frequency powers P1 to P3 are redefined as first and second high-frequency powers P1 and P2, the third high-frequency power P3 becomes the most The power value will be low. In this case, the first and second high-frequency powers P1 and P2 are combined because the matching mismatch due to the third high-frequency power P3 is unlikely to occur and the effect of suppressing the standing wave by the third high-frequency power P3 is added. In some cases, the uniformity of the film thickness and film quality is further improved than in the case.
[0077]
On the other hand, even when the frequency f3 of the third high-frequency power is set outside the range of 10 [MHz] to 250 [MHz] in order to obtain a bias effect, for example, f1, f2 and P1, P2 fall within the scope of the present invention. It can be used without any problems as long as it is properly set. As described above, when further electric power is supplied, it is necessary to make the electric power such that addition of the electric power does not impair the uniformity of the plasma processing characteristics.
[0078]
In the vacuum processing apparatus 1, it is preferable that the cylindrical substrates 11 are arranged at equal intervals along the same circumference centered on the center of the reaction vessel 12. By uniformly disposing the cylindrical substrate 11 in the reaction vessel 12, the ground potential in the reaction vessel 11 is more evenly distributed, so that the uniformity of the plasma distribution in the reaction vessel 11 is further improved, The uniformity of the film thickness and film quality of the deposited film formed on the cylindrical substrate 11 is improved.
[0079]
【Example】
Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto. In each of the vacuum processing apparatuses used in the following examples and comparative examples, the same members as those of the above-described vacuum processing apparatus 1 are denoted by the same reference numerals, and description thereof will be omitted.
[0080]
(Example 1)
As shown in FIGS. 4 and 5, the bottom plate 23 and the cylindrical substrate 11 (outer diameter 80 [mm], thickness 3 [mm], length The distance A from the lower end 31 of the cylindrical aluminum cylinder (mirror-finished to 358 [mm]) was changed from 70 [mm] to 300 [mm]. Under the conditions shown below, a blocking layer, a photoconductive layer, and a surface layer were formed in this order, and seven electrophotographic photosensitive members were produced.
[0081]
In the vacuum processing apparatus 2, an electrode 55 is arranged at the center of the reaction vessel 12. The bottom plate 23 is provided with a plurality of exhaust ports 56 along the outer periphery of the lower end of the electrode 55.
[0082]
As the high-frequency power supply 16, a power supply capable of outputting high-frequency power having a frequency of 105 [MHz] was used. In addition, the type of each gas used at the time of manufacturing the electrophotographic photosensitive member was a constant flow rate in each layer. However, the distance B between the upper end 32 of the cylindrical substrate 11 and the top plate 22 is always 40 [mm] even if the height of the substrate holding member 13 is changed. The flow rate of the raw material gas was adjusted so that the pressure in the reaction vessel 12 became the condition shown in Table 1.
[0083]
[Table 1]

[0084]
With respect to the electrophotographic photosensitive member manufactured under the above-described conditions, the number of spherical projections, thickness unevenness, charging ability unevenness and sensitivity unevenness were measured under the following conditions.
[0085]
(Number of spherical projections)
In the measurement of the number of spherical protrusions, the number of spherical protrusions having a major axis of 10 [μm] or more and existing in a measurement range of 2 [mm] × 2 [mm] was measured. The display of the measurement position was 0 [mm] at the center in the longitudinal direction of the electrophotographic photosensitive member, plus (+) at a position above the center, and minus (-) at a position below the center. The position of -160 [mm] and -170 [mm] in the longitudinal direction at an arbitrary point in the circumferential direction at the center of the electrophotographic photosensitive member, and the-in the longitudinal direction at a point rotated 180 ° in the circumferential direction from the arbitrary point. The total number of spherical projections at 160 [mm] and -170 [mm] positions, that is, a total of four positions was determined. Similarly, seven electrophotographic photosensitive members were measured, and the average of the number of the seven spherical projections was defined as the number of spherical projections. Therefore, the smaller the number of spherical projections, the better the number of spherical projections.
[0086]
(Thickness unevenness)
The film thickness unevenness was measured by setting the center of the electrophotographic photosensitive member in the longitudinal direction to 0 [mm], and measuring a total of 17 film thicknesses from the center 0 [mm] at intervals of 20 [mm] up and down in the longitudinal direction. The measurement was performed to determine the difference between the maximum value and the minimum value of the measured values, and the average of the seven electrophotographic photosensitive members was regarded as the film thickness unevenness. Therefore, the smaller the thickness unevenness, the better the film thickness unevenness.
[0087]
(Chargeability unevenness)
The measurement of the charging ability unevenness was performed by setting an electrophotographic photosensitive member produced under the above-described conditions in an electrophotographic apparatus (manufactured by Canon Inc., iR5000 modified for evaluation), and evaluating potential characteristics. At this time, the developing device of the electrophotographic apparatus is operated under the conditions of a process speed of 265 [mm / sec], a pre-exposure amount (LED of wavelength 660 [nm]) 4 [lux · sec], and a charging device current value 1000 [μA]. The surface potential of the photoreceptor is measured by an electric potential sensor of a surface electrometer (TREK: Model 344) set at a position without irradiating the image exposure (a semiconductor laser having a wavelength of 655 [nm]), and the charging potential is measured. And At the measurement position, the charging ability was measured at the same position as the film thickness measurement, the difference between the maximum value and the minimum value of the measured values was determined, and the average of the seven electrophotographic photosensitive members was defined as the charging ability unevenness. Therefore, the smaller the charging ability unevenness, the better the charging ability unevenness.
[0088]
(Sensitivity unevenness)
The sensitivity unevenness is measured by adjusting the current value of the charger so that the surface potential becomes 400 [V] (dark potential) under the above conditions, and then irradiating with image exposure (a semiconductor laser having a wavelength of 655 [nm]). Then, the light amount of the image exposure light source was adjusted so that the surface potential became 50 [V] (bright potential), and the exposure amount at that time was used as the sensitivity. At the measurement position, the sensitivity was measured at the same position as the film thickness measurement, the difference between the maximum value and the minimum value of the measured values was determined, and the average of seven electrophotographic photosensitive members was regarded as the sensitivity unevenness. Therefore, the smaller the sensitivity unevenness in the longitudinal direction of the electrophotographic photosensitive member, the better the sensitivity unevenness.
[0089]
(Comparative Example 1)
Using the vacuum processing apparatus 2 shown in FIG. 4 in which the distance A between the bottom plate 23 and the lower end 31 of the cylindrical substrate 11 was set to 50 [mm], and in the same manner as in Example 1 under the conditions shown in Table 1, A photoreceptor was prepared. However, the height of the reaction vessel 12 was adjusted so that the distance B between the upper end 32 of the cylindrical substrate 11 and the top plate 22 was 40 [mm].
[0090]
With respect to the electrophotographic photosensitive member manufactured under the above-described conditions, the number of spherical protrusions, thickness unevenness, charging ability unevenness and sensitivity unevenness were measured in the same manner as in Example 1.
[0091]
(Comparative Example 2)
Example 1 was performed under the conditions shown in Table 1 using the vacuum processing apparatus 2 shown in FIGS. 4 and 5 in which the distance A between the bottom plate 23 and the lower end 31 of the cylindrical substrate 11 was set to 400 [mm]. An electrophotographic photoreceptor was produced in the same manner as in the above. However, the height of the reaction vessel 12 was adjusted so that the distance B between the upper end 32 of the cylindrical substrate 11 and the top plate 22 was 40 [mm].
[0092]
With respect to the electrophotographic photosensitive member manufactured under the above-described conditions, the number of spherical protrusions, thickness unevenness, charging ability unevenness and sensitivity unevenness were measured in the same manner as in Example 1.
[0093]
For each of the electrophotographic photoreceptors obtained in Example 1, Comparative Example 1 and Comparative Example 2, the number of spherical projections, film thickness unevenness, charging ability unevenness and sensitivity unevenness were evaluated relative to each measured value of Comparative Example 1 being 100. Was done. Table 2 shows the results.
[0094]
[Table 2]

[0095]
As shown in Table 2, when the distance A between the bottom plate 23 and the lower end 31 of the cylindrical substrate 11 is changed, the number of spherical projections becomes better as the distance is longer, but the number of spherical projections is larger than 300 [mm]. When the length was also increased, exfoliation from the substrate holding member 13 occurred, so that it became worse. In addition, the charging ability unevenness and sensitivity unevenness were similarly deteriorated when the length was longer than 300 [mm] due to the influence of the number of spherical projections. The film thickness unevenness was reduced by separating the cylindrical substrate 11 from the bottom plate 23 by 70 mm or more, and further reduced by separating the cylindrical substrate 11 by 90 mm or more.
[0096]
As a result, by setting the distance A between the bottom plate 23 and the lower end 31 of the cylindrical substrate 11 within the range of 70 [mm] or more and 300 [mm] or less, the number of spherical projections, film thickness unevenness, and charging ability Nonuniformity and sensitivity nonuniformity were reduced, and in particular, were further reduced by setting the range to 90 [mm] or more and 220 [mm] or less.
[0097]
(Example 2)
As shown in FIG. 7, the vacuum processing apparatus 4 has the same basic configuration as the vacuum processing apparatus 2 shown in FIG. 4, and includes a reaction vessel 52 having a side wall 61 formed of alumina as a dielectric material. is there. The vacuum processing apparatus 4 is provided with a substantially L-shaped exhaust pipe 57 at an exhaust port 56 of the reaction vessel 52. As shown in FIGS. 9 and 10, the vacuum processing device 6 is a device in which the high-frequency electrode 15 is arranged outside the reaction vessel 52 in the vacuum processing device 4 shown in FIG.
[0098]
The blocking layer, the photoconductive layer, and the surface layer were formed in this order on the cylindrical substrate 11 using the vacuum processing apparatuses 4 and 6 in the same manner as in Example 1 under the conditions shown in Table 1. Was prepared. At this time, a power supply capable of outputting high-frequency power having a frequency of 105 [MHz] was used as the high-frequency power supply 16. In addition, the type of each gas used at the time of manufacturing the electrophotographic photosensitive member was a constant flow rate in each layer. However, the distance A between the bottom plate 23 and the lower end 31 of the cylindrical base 11 is set to 90 [mm], and the distance B between the upper end 32 of the cylindrical base 11 and the top plate 22 is set to 40 [mm]. Set.
[0099]
With respect to the electrophotographic photosensitive member manufactured under the above-described conditions, the number of spherical protrusions, thickness unevenness, charging ability unevenness and sensitivity unevenness were measured in the same manner as in Example 1, and the bottom plate 23 and the lower end of the cylindrical substrate 11 in Example 1 were measured. A comparison was made with an electrophotographic photosensitive member produced by setting the distance A between the photosensitive member and the photosensitive member 31 to 90 [mm].
[0100]
With respect to the electrophotographic photoreceptor obtained in Example 2, the number of spherical protrusions, the thickness unevenness, the charging ability unevenness and the sensitivity unevenness were evaluated relative to each other in Comparative Example 1 as 100. Table 3 shows the results.
[0101]
[Table 3]

[0102]
As shown in Table 3, by changing the side wall 61 constituting the reaction vessel 52 to a dielectric material, no change was observed in the film thickness unevenness. And the number of spherical projections decreased. In addition, since the number of spherical projections was reduced, unevenness in charging ability and unevenness in sensitivity were also reduced. Next, by arranging the high-frequency electrode 15 outside the reaction vessel 52, the amount of dust in the reaction vessel 52 was further reduced, so that the number of spherical projections was reduced, and the charging ability unevenness and sensitivity unevenness were also reduced. Further, by disposing the high-frequency electrode 15 outside the reaction vessel 52, the supply of the high-frequency power into the reaction vessel 52 was made more uniform, so that the film thickness unevenness was reduced.
[0103]
As a result, by forming at least a part of the inner wall constituting the reaction vessel 52 with a dielectric material, the quality of the deposited film formed on the cylindrical substrate 11 was improved, and the number of spherical projections was reduced. . Further, by disposing the high-frequency electrode 15 outside the reaction vessel 52, the film thickness and the film quality were further uniformed, and the number of spherical projections was reduced.
[0104]
(Example 3)
As shown in FIG. 6, the bottom plate 23 and the cylindrical substrate 11 (outer diameter 80 [mm], thickness 3 [mm], length 358) are formed by using the vacuum processing device 3 in which the height of the reaction vessel 12 can be changed. By changing the distance A from the lower end 31 of the mirror-finished aluminum cylinder (mm) from 70 [mm] to 300 [mm] on the cylindrical substrate 11 under the conditions shown in Table 4 A layer, a photoconductive layer, and a surface layer were formed in this order to prepare seven electrophotographic photosensitive members.
[0105]
At this time, a power supply capable of outputting high-frequency power having a frequency of 105 [MHz] and 60 [MHz] was used as the high-frequency power supply 16. In addition, the type of each gas used at the time of manufacturing the electrophotographic photosensitive member was a constant flow rate in each layer. However, the distance B between the upper end 32 of the cylindrical substrate 11 and the top plate 22 is always 40 [mm] even when the height of the substrate holding member 13 in the axial direction is changed. The height was changed, and the flow rate of the raw material gas was adjusted such that the pressure in the reaction vessel 12 became the condition shown in Table 4.
[0106]
[Table 4]

[0107]
With respect to the electrophotographic photosensitive member manufactured under the above-described conditions, the number of spherical protrusions, thickness unevenness, charging ability unevenness and sensitivity unevenness were measured in the same manner as in Example 1.
[0108]
(Comparative Example 3)
As shown in FIG. 6, using the vacuum processing apparatus 3 in which the distance A between the bottom plate 23 and the lower end 31 of the cylindrical substrate 11 was set to 50 [mm], the conditions shown in Table 4 and Example 3 were used. Similarly, an electrophotographic photosensitive member was produced. However, the height of the reaction vessel 12 was adjusted so that the distance B between the upper end 32 of the cylindrical substrate 11 and the top plate 22 was 40 [mm].
[0109]
With respect to the electrophotographic photosensitive member manufactured under the above-described conditions, the number of spherical protrusions, thickness unevenness, charging ability unevenness and sensitivity unevenness were measured in the same manner as in Example 1.
[0110]
(Comparative Example 4)
Using the vacuum processing apparatus 3 shown in FIG. 6 in which the distance A between the bottom plate 23 and the lower end 31 of the cylindrical substrate 11 was set to 400 [mm], in the same manner as in Example 3 under the conditions shown in Table 4 An electrophotographic photosensitive member was manufactured. However, the height of the reaction vessel 12 was adjusted so that the distance B between the upper end 32 of the cylindrical substrate 11 and the top plate 22 was 40 [mm].
[0111]
With respect to the electrophotographic photosensitive member manufactured under the above-described conditions, the number of spherical protrusions, thickness unevenness, charging ability unevenness and sensitivity unevenness were measured in the same manner as in Example 1.
[0112]
For each of the electrophotographic photoreceptors obtained in Example 3, Comparative Example 3 and Comparative Example 4, the number of spherical projections, film thickness unevenness, charging ability unevenness and sensitivity unevenness were evaluated relative to each measured value of Comparative Example 3 being 100. Was done. Table 5 shows the results.
[0113]
[Table 5]

[0114]
As shown in Table 5, when the distance A between the bottom plate 23 and the lower end 31 of the cylindrical base 11 is changed, the number of spherical projections becomes better as the distance A is longer, but 300 [mm]. In the case where the length is longer, peeling off from the base holding member 13 occurs as in the case of the first embodiment, so that it is deteriorated. In addition, the charging ability unevenness and sensitivity unevenness were similarly deteriorated when the length was longer than 300 [mm] due to the number of spherical projections. The thickness unevenness was reduced by separating the lower end 31 of the cylindrical substrate 11 from the bottom plate 23 by 70 mm or more, and further reduced by separating the lower end 31 by 90 mm or more. Furthermore, by using high-frequency power of a plurality of frequencies, it is possible to suppress a standing wave generated when using high-frequency power of a single frequency. The number of protrusions has been reduced.
[0115]
As a result, even when a plurality of high-frequency powers are used, the distance A between the bottom plate 23 and the lower end 31 of the cylindrical base 11 is set within the range of 70 mm or more and 300 mm or less. , The number of spherical projections, the film thickness unevenness, the charging ability unevenness and the sensitivity unevenness are reduced. In particular, by setting the range of 90 [mm] to 220 [mm], the effect is further reduced. Was better than when high-frequency power was used.
[0116]
(Example 4)
As shown in FIG. 8, the vacuum processing apparatus 5 has the same basic configuration as the vacuum processing apparatus 3 shown in FIG. 6, and includes a reaction vessel 52 having a side wall 61 formed of alumina as a dielectric material. is there. As shown in FIG. 11, the vacuum processing device 7 is a device in which the high-frequency electrode 15 is arranged outside the reaction vessel 52 in the vacuum processing device 5 shown in FIG.
[0117]
Using the vacuum processing apparatuses 5 and 7, the blocking layer, the photoconductive layer, and the surface layer were formed in this order on the cylindrical substrate 11 in the same manner as in Example 3 under the conditions shown in Table 4, and the electrophotographic photoreceptor was formed. Was prepared. At this time, a power supply capable of outputting high-frequency power having a frequency of 105 [MHz] and 60 [MHz] was used as the high-frequency power supply. In addition, the type of each gas used at the time of manufacturing the electrophotographic photosensitive member was a constant flow rate in each layer. However, the distance A between the bottom plate 23 and the lower end 31 of the cylindrical base 11 was set to 90 [mm], and the distance B between the upper end 32 of the cylindrical base 11 and the top plate 22 was set to 40 [mm].
[0118]
The number of spherical protrusions, thickness unevenness, charging ability unevenness and sensitivity unevenness of the electrophotographic photoreceptor manufactured under the above-described conditions were measured in the same manner as in Example 1. The relative comparison was made with an electrophotographic photosensitive member manufactured by setting the distance A between the photosensitive member and the photosensitive member to 90 [mm].
[0119]
With respect to the electrophotographic photosensitive member obtained in Example 4, the number of spherical projections, the film thickness unevenness, the charging ability unevenness, and the sensitivity unevenness were relatively evaluated with each measured value of Comparative Example 3 being 100. Table 6 shows the results.
[0120]
[Table 6]

[0121]
As shown in Table 6, by changing the side wall 61 constituting the reaction vessel 52 to a dielectric material, dust causing spherical projections such as film fragments generated in the reaction vessel 52 was reduced. Diminished. In addition, since the number of spherical projections was reduced, unevenness in charging ability and unevenness in sensitivity were also reduced. In addition, by supplying high-frequency powers of a plurality of frequencies, thickness unevenness was slightly reduced. Next, by arranging the high-frequency electrode 15 outside the reaction vessel 52, the amount of dust in the reaction vessel 52 was further reduced, so that the number of spherical projections was reduced, and the charging ability unevenness and sensitivity unevenness were also reduced. Further, by disposing the high-frequency electrode 15 outside the reaction vessel 52, the supply of the high-frequency power into the reaction vessel 52 was made more uniform, so that the film thickness unevenness was reduced. Furthermore, by using high-frequency power of a plurality of frequencies, it is possible to suppress a standing wave generated when using high-frequency power of a single frequency. The number of protrusions has been reduced.
[0122]
As a result, even when a plurality of high-frequency powers are used, at least a part of the inner wall constituting the reaction vessel 52 is formed of a dielectric material, so that the film quality of the deposited film formed on the cylindrical substrate 11 is improved. And the number of spherical projections was also reduced. Further, by disposing the high-frequency electrode 15 outside the reaction vessel 52, the film thickness and film quality were further improved, and the number of spherical projections was reduced.
[0123]
(Example 5)
As shown in FIGS. 12 and 13, the bottom plate 23 and the cylindrical substrate 11 (outside) are provided by using a vacuum processing device 8 having electrodes 65 inside and outside the reaction vessel 52 and capable of changing the height of the reaction vessel 52. The distance A between the lower end 31 of the mirror-finished aluminum cylinder having a diameter of 80 [mm], a thickness of 3 [mm] and a length of 358 [mm] was changed from 70 [mm] to 300 [mm]. Then, a blocking layer, a photoconductive layer, and a surface layer were formed in this order on the cylindrical substrate 11 in the same manner as in Example 3 under the conditions shown in Table 4 to produce an electrophotographic photosensitive member.
[0124]
At this time, as the high-frequency power supplies 16 and 17, power supplies capable of outputting high-frequency power having frequencies of 105 [MHz] and 60 [MHz] were used. In addition, the type of each gas used at the time of manufacturing the electrophotographic photosensitive member was a constant flow rate in each layer. However, the distance B between the upper end 32 of the cylindrical substrate 11 and the top plate 22 is always 40 [mm] even when the height of the substrate holding member 13 is changed. Changed height. Further, the flow rate of the raw material gas was adjusted such that the pressure in the reaction vessel 52 became the condition shown in Table 4.
[0125]
With respect to the electrophotographic photosensitive member manufactured under the above-described conditions, the number of spherical projections, thickness unevenness, charging ability unevenness and sensitivity unevenness were measured in the same manner as in Example 1.
[0126]
(Comparative Example 5)
Using the vacuum processing apparatus 8 shown in FIG. 12 in which the distance A between the bottom plate 23 and the lower end 31 of the cylindrical substrate 11 was set to 50 [mm], under the conditions shown in Table 4, the same as in Example 3 An electrophotographic photosensitive member was manufactured. However, the height of the reaction vessel 52 was adjusted so that the distance B between the upper end 32 of the cylindrical substrate 11 and the top plate 22 was 40 [mm].
[0127]
With respect to the electrophotographic photosensitive member manufactured under the above-described conditions, the number of spherical protrusions, thickness unevenness, charging ability unevenness and sensitivity unevenness were measured in the same manner as in Example 1.
[0128]
(Comparative Example 6)
Using the vacuum processing device 8 shown in FIG. 12 in which the distance A between the bottom plate 23 and the lower end 31 of the cylindrical substrate 11 was set to 400 [mm], in the same manner as in Example 3 under the conditions shown in Table 4 An electrophotographic photosensitive member was manufactured. However, the height of the reaction vessel 52 was adjusted so that the distance B between the upper end 32 of the cylindrical substrate 11 and the top plate 22 was 40 [mm].
[0129]
With respect to the electrophotographic photosensitive member manufactured under the above-described conditions, the number of spherical protrusions, thickness unevenness, charging ability unevenness and sensitivity unevenness were measured in the same manner as in Example 1.
[0130]
For each of the electrophotographic photoreceptors obtained in Example 5, Comparative Example 5, and Comparative Example 6, the number of spherical protrusions, film thickness unevenness, charging ability unevenness and sensitivity unevenness were evaluated relative to each measured value of Comparative Example 5 being 100. Was done. Table 7 shows the results.
[0131]
[Table 7]

[0132]
As shown in Table 7, as a result of changing the configuration of the vacuum processing apparatus under the same conditions as in Example 3, the number of spherical projections becomes better as the above-described distance A increases, but the number of spherical projections increases. When it was larger than 300 [mm], as in Examples 1 and 3, peeling from the substrate holding member occurred, so that the deterioration became worse. In addition, the charging ability unevenness and the sensitivity unevenness also deteriorated when the thickness was larger than 300 [mm] due to the influence of the number of spherical projections. The thickness unevenness was reduced by separating the lower end 31 of the cylindrical substrate 11 from the bottom plate 23 by 70 mm or more, and further reduced by separating the lower end 31 by 90 mm or more.
[0133]
As a result, even when the configuration of the vacuum processing apparatus is changed, by setting the distance A between the bottom plate 23 and the lower end 31 of the cylindrical base 11 to be not less than 70 [mm] and not more than 300 [mm], The number of spherical projections, film thickness unevenness, charging ability unevenness and sensitivity unevenness were reduced, and in particular, were further reduced by setting it to 90 [mm] or more and 220 [mm] or less.
[0134]
【The invention's effect】
As described above, according to the vacuum processing apparatus of the present invention, the distance A between the inner surface of the bottom plate constituting the reaction vessel and the lower end of the substrate to be processed satisfies the condition of 70 mm ≦ A ≦ 300 mm, It is possible to reduce spherical projections generated in the deposited film formed on the substrate to be processed. According to the vacuum processing apparatus of the present invention, it is possible to form a deposited film on the substrate to be processed in a region where the plasma in the vacuum processing space is uniform. The uniformity of thickness and film quality can be improved, and the productivity can be improved.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a vacuum processing apparatus according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view of the vacuum processing apparatus shown in FIG.
FIG. 3 is a longitudinal sectional view of a lower portion of a reaction vessel provided in the vacuum processing apparatus shown in FIG.
FIG. 4 is a longitudinal sectional view of a vacuum processing apparatus used in Example 1 and Comparative Examples 1 and 2.
FIG. 5 is a cross-sectional view of the vacuum processing apparatus shown in FIG.
FIG. 6 is a longitudinal sectional view of a vacuum processing apparatus used in Example 3 and Comparative Examples 3 and 4.
FIG. 7 is a longitudinal sectional view of a vacuum processing apparatus used in a second embodiment.
FIG. 8 is a vertical sectional view of a vacuum processing apparatus used in a fourth embodiment.
FIG. 9 is a vertical sectional view of a vacuum processing apparatus used in Embodiment 2.
FIG. 10 is a cross-sectional view of the vacuum processing apparatus shown in FIG.
FIG. 11 is a longitudinal sectional view of a vacuum processing apparatus used in a fourth embodiment.
FIG. 12 is a longitudinal sectional view of a vacuum processing apparatus used in Example 5 and Comparative Examples 5 and 6.
FIG. 13 is a cross-sectional view of the vacuum processing apparatus shown in FIG.
FIG. 14 is a schematic view of a conventional apparatus for manufacturing an electrophotographic photosensitive member by a high-frequency plasma CVD method.
15 is a cross-sectional view of a vacuum processing apparatus provided in the apparatus for manufacturing an electrophotographic photosensitive member shown in FIG.
[Explanation of symbols]
1-8 vacuum processing equipment
11 Cylindrical substrate
12 reaction vessels
13 Substrate holding member
14 Gas supply pipe
15 High frequency electrode
16, 17 Power supply source
18 Matching box
19 Auxiliary member
21 Side wall
22 Top plate
23 Bottom plate
24 plasma processing space
26 exhaust port
27 Exhaust piping
28 heater
31 lower end
32 upper end
34 motor
35 Reduction gear
36 rotation axis
37 Electromagnetic shielding
101 vacuum processing equipment
102 Gas supply device
111 Cylindrical substrate
112 reaction vessel
113 Substrate holding member
114 gas supply pipe
115 High frequency electrode
116,117 Power supply source
118 Matching Box
119 Auxiliary member
121 Side wall
122 Top Plate
123 bottom plate
126 exhaust port
127 Exhaust piping
128 heater
134 motor
135 reduction gear
136 rotation axis
191 to 195 mass flow controller
151-155 Raw material gas cylinder
161 to 165 cylinder valve
171-175 Inflow valve
181-185 Outflow valve
196-200 pressure regulator
201 Main valve

Claims (1)

被処理基体に真空処理を施すための減圧可能な反応容器と、被処理基体を保持するための基体保持部材と、前記反応容器内に処理用ガスを導入するためのガス導入手段と、前記反応容器内に導入された処理用ガスを励起してグロー放電を発生させる高周波電力を供給可能な高周波電力供給手段とを備える真空処理装置であって、
前記反応容器は、前記反応容器内を真空に排気するための排気口が設けられた底板を有し、
前記底板の内面と、前記基体保持部材に保持された前記被処理基体の下端との間の距離Ａが、７０ｍｍ≦Ａ≦３００ｍｍの条件を満たすことを特徴とする真空処理装置。A reaction vessel capable of performing vacuum processing on the substrate to be processed, a substrate holding member for holding the substrate to be processed, gas introducing means for introducing a processing gas into the reaction vessel, A vacuum processing apparatus comprising: a high-frequency power supply unit capable of supplying high-frequency power for generating a glow discharge by exciting the processing gas introduced into the container;
The reaction vessel has a bottom plate provided with an exhaust port for evacuating the inside of the reaction vessel to a vacuum,
A vacuum processing apparatus, wherein a distance A between an inner surface of the bottom plate and a lower end of the substrate to be processed held by the substrate holding member satisfies a condition of 70 mm ≦ A ≦ 300 mm.

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