JP3548335B2 - Deposited film forming apparatus and deposited film forming method - Google Patents

Description

こうして測定した電子温度の分布を図６に示した。図６において飽和電子電流の値は最も大きい値を１として規格化して示した。図６から明らかな様に本発明の高周波導入手段では放電の偏りは観測されなかった。
【００３８】
＜比較実験例１＞
図５に示した堆積膜形成装置に従来の高周波導入手段を設置し、実験例１と全く同様にプラズマの偏りを測定した。本実験例で使用した高周波導入手段は電極をムクの金属の円柱とし、インピーダンスの不連続面は設けなかった。なお電極の径は、実験例１で使用したもの電極の外径（絶縁体の内径）と同一であり、全長も同一である。
こうして測定した結果を図７に示す。図７において飽和電子電流の値は実験例１の場合と同様に最も大きい値を１として規格化して示した。図７の結果から明らかな様に従来の高周波導入手段ではプラズマの偏りが観測された。
【００３９】
＜比較実験例２＞
図５に示した堆積膜形成装置に電極に絶縁体のカバーを設けない（電極表面がプラズマに晒される）従来の高周波導入手段を設置し、実験例１と全く同様にプラズマの偏りを測定した。本実験例で使用した高周波導入手段は電極を実験例１で用いた高周波導入手段と全く同様のインピーダンスの不連続面を形成した電極を用いた。こうして測定した結果を図８に示す。図８において飽和電子電流の値は実験例１の場合と同様に最も大きい値を１として規格化して示した。図８の結果から明らかな様に従来の高周波導入手段ではプラズマの偏りが観測された。
【００４０】
＜比較実験例３＞
図５に示した堆積膜形成装置に従来の高周波導入手段を設置し、実験例１と全く同様にプラズマの偏りを測定した。本実験例で使用した高周波導入手段は電極を実験例１で用いた高周波導入手段と全く同様のインピーダンスの不連続面を形成した電極に絶縁体のカバーを施した。なおカバーと電極の隙間は０．５ｍｍ程度であった。こうして測定した結果を図９に示す。図９において飽和電子電流の値は実験例１の場合と同様に最も大きい値を１として規格化して示した。図９の結果から明らかな様に従来の高周波導入手段ではプラズマの偏りが観測された。
【００４１】
（実験例２）
図５に示した堆積膜形成装置に図１に示した本発明の高周波導入手段を設置し、図１０にしめすような基体１００２上に電荷注入阻止層１００３、光導電層１００４、表面層１００５を順次積層した層構成の電子写真用光受容部材１００１電子写真用光受容部材を作成した。放電条件を以下表２に示す。
【００４２】
【表２】

なお上記表２中の「層厚」は電子写真用光受容部材設計上のおおよその目安である。
【００４３】
本実験例では母材となる絶縁体の材質をアルミナセラミックスとし、グロー放電領域側の表面粗さ（２．５ｍｍを基準長さとする１０点平均粗さ）を約１μｍから約２００μｍまで変化させた。こうして作成した電子写真用光受容部材について、球状突起の数を評価した。なお球状突起の数は次の様にして評価した。各々の電子写真用光受容部材の表面を光学顕微鏡で観察し、１０ｃｍ２あたりの直径１０μｍ以上の球状突起の個数を調べた。また球状突起の個数については、同時に形成される電子写真用光受容部材８本全てについて測定した後、全体を平均値した値を採用した。
【００４４】
＜比較実験例４＞
図５に示した堆積膜形成装置に電極表面にアルミナセラミックスをプラズマ溶射した従来の電極を用い表面粗さを約１μｍから約２００μｍまで変化させ、実験例２と同様にして電子写真用光受容部材を作成した。
こうして作成した電子写真用光受容部材を実験例２と同様にして球状突起の数を評価した。
【００４５】
＜比較実験例５＞
図５に示した堆積膜形成装置に電極表面に絶縁体の被覆を設けない（金属電極のみ）従来の電極を用い表面粗さを約１μｍから約２００μｍまで変化させ、実験例２と同様にして電子写真用光受容部材を作成した。こうして作成した電子写真用光受容部材を実験例２と同様にして球状突起の数を評価した。
以上実験例２および比較実験例４、５の結果を合わせて図１１に示す。図１１において球状突起の値は実験例２の表面粗さ約２８μｍの時の値を１として相対評価で表した。図１１によればいずれの電極も表面を粗くしていくと膜剥れが抑えられ球状突起が減少する傾向が見られるが、実験例２の本発明の高周波導入手段が最も球状突起の発生の防止に効果があり、いずれも良好な結果が得られた。一方で、比較実験例４の高周波導入手段（アルミナセラミックスをプラズマ溶射したもの）では、表面粗さを粗くすると、ある粗さまでは球状突起が減少するが、さらに粗くすると逆に球状突起が増加する傾向がある。これは溶射体の結着力が弱くなって溶射体自体の剥れが発生したためと考えられる。
また比較実験例４、５の場合には放電中にスパークが観測された。
【００４６】
（実験例３）
図５に示した堆積膜形成装置に図１に示した本発明の高周波導入手段を設置し、図１０にしめすような基体１００２上に電荷注入阻止層１００３、光導電層１００４、表面層１００５を順次積層した層構成の電子写真用光受容部材１００１電子写真用光受容部材を作成した。なお高周波導入手段の母材となる絶縁体の材料には二酸化チタンを用いた。本実験例では光導電層中の周波数１０５ＭＨｚの高周波で電力を変化させ電子写真用光受容部材を形成した。その放電条件を以下表３に示す。
【００４７】
【表３】

なお上記表３中の「層厚」は電子写真用光受容部材設計上のおおよその目安である。
こうして作成した電子写真用光受容部材を画像濃度ムラ、球状突起の数、黒ポチについて評価した。なお、球状突起の数については実験例２と同様に、また画像濃度ムラ、黒ポチについては以下の要領で評価した。
（１）画像濃度ムラ
各々の電子写真用光受容部材を電子写真装置（キヤノン社製ＮＰ６０６０を本テスト用に改造したもの）にセットして、キヤノン製中間調チャート（部品番号：ＦＹ９−９０４２）を原稿台に置きコピーしたときに得られたコピー画像上の任意の５０点の画像濃度を反射濃度計で測定し、各々の電子写真用光受容部材について最も画像濃度が濃い部分に対する最も画像濃度が薄い部分の割合を算出し、さらに同時に作成される電子写真用光受容部材８本全てについて上記の測定を行ない最終的にそれらの割合を平均した値を画像濃度ムラとして比較した。
（２）黒ポチ
各々の電子写真用光受容部材を電子写真装置（キヤノン社製ＮＰ６０６０を本テスト用に改造したもの）にセットして、キヤノン製中間調チャート（部品番号：ＦＹ９−９０４２）を原稿台に置きＡ４サイズのコピー用紙を用いて３００万枚画像形成を繰り返した。途中１万枚毎に原稿台に白紙を置き得られたコピー画像上の黒ポチを検査した。評価においては以下に示す４段階の評価を用いた。
◎きわめて良好
○良好
△実用上問題なし
×問題あり
以上の結果を表４に示す。
【００４８】
【表４】

表４において画像濃度ムラ、球状突起についてはそれぞれ高周波電力１５００Ｗの時を１として相対評価で表した。表４の結果より本発明の堆積膜形成装置では図すべての項目に渡って良好な結果が得られた。
【００４９】
＜比較実験例６＞
図５に示した堆積膜形成装置にインピーダンスの不連続なパターンを設けない電極を用い、実験例３と同様にして電子写真用光受容部材を作成した。こうして作成した電子写真用光受容部材を実験例３と同様にして画像濃度ムラ、球状突起の数、黒ポチを評価した。その結果を表５に示す。
【００５０】
【表５】

表５において画像濃度ムラ、球状突起についてはそれぞれ実験例３の高周波電力１５００Ｗの時を１として相対評価で表した。本比較実験例で使用した高周波導入手段では、高周波電力を上げていくに従って画像濃度ムラが改善される一方、黒ポチが悪化する。これは高周波の放射が片寄っていることにより、部分的に高周波電力が集中して、膜の成長に影響を与えているためと考えられる。
【００５１】
＜比較実験例７＞
図５に示した堆積膜形成装置に電極表面に絶縁体の被覆を設けない（金属電極のみ）以外は実験例３と同様の電極を用い、実験例３と同様にして電子写真用光受容部材を作成した。こうして作成した電子写真用光受容部材を実験例３と同様にして画像濃度ムラ、球状突起の数、黒ポチを評価した。その結果を表６に示す。
【００５２】
【表６】

表６において画像濃度ムラ、球状突起についてはそれぞれ実験例３の高周波電力１５００Ｗの時を１として相対評価で表した。表６の結果より、本比較実験例で用いた高周波導入手段では実験例３で用いた本発明の高周波導入手段に比べて、インピーダンスの不連続面の効果が余り得られなかった。また、主に高周波導入手段からの堆積膜の剥離の影響で球状突起が多く発生した。
【００５３】
（実験例４）
図５に示した堆積膜形成装置に図１に示した本発明の高周波導入手段を設置し、図１０にしめすような基体１００２上に電荷注入阻止層１００３、光導電層１００４、表面層１００５を順次積層した層構成の電子写真用光受容部材１００１電子写真用光受容部材を作成した。なお、高周波導入手段の母材となる絶縁体の材料は窒化アルミニウムを使用した。本実験例では高周波電力の周波数を変化させ電子写真用光受容部材を形成した。その放電条件を以下表７に示す。
【００５４】
【表７】

なお上記表７中の「層厚」は電子写真用光受容部材設計上のおおよその目安である。
こうして作成した電子写真用光受容部材を画像濃度ムラ、球状突起の数、黒ポチについて評価した。その結果を表８に示す。
【００５５】
【表８】

表８中の×はこの条件では放電が安定して維持できず、電子写真用光受容部材の形成ができなかったことを示す。表８の結果から、周波数２０ＭＨｚから４５０ＭＨｚの範囲ではいずれの項目もきわめて良好な結果が得られた。一方周波数を８００ＭＨｚとした場合には、放電は維持したものの、高周波の整合条件が安定せず、画像濃度ムラが大きくなる結果となった。
【００５６】
［実施例１］
図５に示した堆積膜形成装置に図１に示した本発明の高周波導入手段を設置し、図１０に示した層構成の電子写真用光受容部材を作成した。本実施例では高周波導入手段の母材となる絶縁体の材料はアルミナセラミックスを用いた。その放電条件を表９に示す。
【００５７】
【表９】

なお上記表９中の「層厚」は電子写真用光受容部材設計上のおおよその目安である。こうして作成した電子写真用光受容部材を球状突起の数、膜厚ムラ、画像濃度ムラについて評価した。
【００５８】
［実施例２］
図５に示した堆積膜形成装置に図２に示した本発明の高周波導入手段を設置し、図１０に示した層構成の電子写真用光受容部材を作成した。本実施例では高周波導入手段の母材となる絶縁体の材料はアルミナセラミックスを用いた。その放電条件を表１０に示す。
【００５９】
【表１０】

なお上記表１１中の「層厚」は電子写真用光受容部材設計上のおおよその目安である。こうして作成した電子写真用光受容部材を球状突起の数、膜厚ムラ、画像濃度ムラについて評価した。
【００６０】
［実施例３］
図５に示した堆積膜形成装置に図３に示した本発明の高周波導入手段を設置し、図１０に示した層構成の電子写真用光受容部材を作成した。本実施例では高周波導入手段の母材となる絶縁体の材料は二酸化チタンを用いた。その放電条件を表１１に示す。
【００６１】
【表１１】

なお上記表１１中の「層厚」は電子写真用光受容部材設計上のおおよその目安である。こうして作成した電子写真用光受容部材を球状突起の数、膜厚ムラ、画像濃度ムラについて評価した。
【００６２】
［実施例４］
図５に示した堆積膜形成装置に図４に示した本発明の高周波導入手段を設置し、図１０に示した層構成の電子写真用光受容部材を作成した。本実施例では高周波導入手段の母材となる絶縁体の材料はアルミナセラミックスを用いた。その放電条件を表１２に示す。
【００６３】
【表１２】

なお上記表１２中の「層厚」は電子写真用光受容部材設計上のおおよその目安である。こうして作成した電子写真用光受容部材を球状突起の数、膜厚ムラ、画像濃度ムラについて評価した。
【００６４】
［実施例５］
図１２に示した堆積膜形成装置に図４に示した本発明の高周波導入手段を設置し、図１０に示した層構成の電子写真用光受容部材を作成した。本実施例では高周波導入手段の母材となる絶縁体の材料はアルミナセラミックスを用いた。図１２の装置では、高周波導入手段１０２が、基体１０１の配置円の外部に８本と基体１０１の配置円の内部に１本設置されている。各々の高周波導入手段１０２はマッチングボックス１０６を介して、高周波電源（不図示）に接続されている。図１２の例では、グロー放電が基体の配置円の内部と外部に均一に広がるため、図５の装置のような、基体１０１の回転機構は必ずしも必要としない。図１２の装置では、基体１０１は支持軸１２２に固定されている。
図１２に示した装置を用いた電子写真用光受容部材作成の条件を表１３に示す。
【００６５】
【表１３】

なお上記表１３中の「層厚」は電子写真用光受容部材設計上のおおよその目安である。こうして作成した電子写真用光受容部材を球状突起の数、膜厚ムラ、画像濃度ムラについて評価した。
以上実施例１から５の結果をまとめて表１４に示す。
【００６６】
【表１４】

上記表１４において球状突起の数及び画像濃度ムラについてはそれぞれ実施例１の値を１とした相対評価で示した。表１４から明らかな様に本発明の堆積膜形成装置では、いずれも良好な特性が得られた。
【００６７】
【発明の効果】
本発明は、以上のように、その高周波電力導入手段は、プラズマに接する表面が絶縁体を母材で覆われているため、堆積膜の密着性が良好で、コーティング材の剥離が発生せず、また、電極が絶縁材料で覆われているため、インピーダンスの不連続面が高周波電力の反射面として効果的に作用し高周波電力の均一化を図ることができ、それと共にインピーダンスの不連続面をもつ複雑な電極の構造であってもスパークの発生をも効果的に防止できる。さらに電極が絶縁材料の内側に密着生成されるので、電極と絶縁材料との隙間に起因する高周波電力のムラの発生を防止することができる。
【００６８】
したがって、本発明によると、電子写真用光受容部材を作成する上で問題となる、球状突起の発生、画像濃度ムラ、黒ポチの発生を効果的に抑制し、きわめて高品質な電子写真用光受容部材を形成することができる。
【図面の簡単な説明】
【図１】本発明の電極の一部を複数に分岐してインピーダンスを不連続にした高周波導入手段の一例を示す模式図である。
【図２】本発明の電極の一部を折り返すことによってインピーダンスを不連続にした高周波導入手段の一例を示す模式図である。
【図３】本発明の電極の一部をコイル形状とすることによってインピーダンスを不連続にした高周波導入手段の一例を示す模式図である。
【図４】本発明の冷却機構を設けた高周波導入手段の一例を示す模式図である。
【図５】本発明の円筒状基体を同一円周上に配置した堆積膜形成装置の一例を示す模式図である。
【図６】実験例１における本発明の堆積膜形成装置での飽和電子電流の分布を示すグラフである。
【図７】比較実験例１における飽和電子電流の分布を示すグラフである。
【図８】比較実験例２における飽和電子電流の分布を示すグラフである。
【図９】比較実験例３における飽和電子電流の分布を示すグラフである。
【図１０】各実施例等に置いて作成した電子写真用光受容部材の層構成の一例を示す断面模式図である。
【図１１】実験例２および比較実験例４、５における球状突起の数を示すグラフである。
【図１２】本発明の堆積膜形成装置の一例を示す模式図である。
【符号の説明】
１００：反応容器
１０１：基体
１０２：高周波導入手段
１０３：グロー放電領域
１０４：基体加熱用ヒーター
１０５：原料ガス導入手段
１０６：高周波マッチングボックス
１０７：電源
１０８：回転軸
１０９：モーター
１１０：ギア
１１１：絶縁体
１１２：電極
１１３：空洞
１１９：冷媒供給口
１２０：冷媒導入パイプ
１２１：冷媒排出口
１２２：支持軸
１００１：電子写真用光受容部材
１００２：基体
１００３：電荷注入阻止層
１００４：光導電層
１００５：表面層[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a deposited film forming apparatus and a deposited film forming method for forming a deposited film on a cylindrical conductive substrate, and particularly relates to a functional deposited film, particularly a semiconductor device, a light receiving member for electrophotography, a line sensor for image input, The present invention relates to an apparatus and a method for forming a deposited film by plasma CVD for forming an amorphous semiconductor used in an imaging device, a photovoltaic device, and the like.
[0002]
[Prior art]
As an element member used for a semiconductor device, a light receiving member for electrophotography, a line sensor for image input, an imaging device, a photovoltaic device, and various other electronic elements, amorphous silicon, for example, hydrogen or / and halogen compensated. Deposited films for semiconductors and the like made of amorphous materials such as amorphous silicon have been proposed, and some of them have been put to practical use.
For example, Japanese Patent Application Laid-Open No. 54-86341 discloses a technique relating to a light receiving member for electrophotography using a-Si for a photoconductive layer and having excellent moisture resistance, durability, and electric characteristics.
Japanese Patent Application Laid-Open No. Sho 62-168161 describes a technique using, as a surface layer, a material composed of an amorphous material containing silicon atoms, carbon atoms, and 41 to 70 atomic% of hydrogen atoms as constituent elements. ing.
Practical use as an electrophotographic light-receiving member made of amorphous silicon, which can improve the electrical, optical and photoconductive properties, the usage environment properties and the durability, and further improve the image quality. Is progressing.
[0003]
On the other hand, the production of amorphous silicon devices requires advanced technology. In particular, light receiving members for electrophotography require a large area and a large film thickness as compared with other devices, so how to ensure uniformity and how to deposit amorphous silicon film An important factor is how to prevent abnormal growth of the film, which is generated by using foreign matter as nuclei therein.
[0004]
From such a viewpoint, various proposals have been made on how to stably produce a high-quality amorphous silicon deposition film industrially.
In particular, with regard to the electrophotographic light-receiving member, there is a problem in that spherical projections which cause so-called "white spots", which cause fine white spots on a copy image, cause image defects. It is considered that most of the causes of the generation of such spherical projections are that, during the formation of the deposited film, fragments generated by peeling of the film generated inside the deposited film forming apparatus adhere to the surface of the substrate, causing abnormal growth of the film.
Further, unevenness in which the image density varies depending on a portion on a copy image obtained by an electrophotographic apparatus also poses a problem, and proposals have been made for improving these.
[0005]
For example, Japanese Patent Application Laid-Open No. Hei 4-183871 discloses a technique in which a microwave introducing means is constituted by two different regions in a deposited film forming apparatus. According to the publication, the product of the dielectric constant and the dielectric contact at the frequency of the microwave using the surface of the microwave introducing means that contacts the plasma is 2 × 10^-2It is stated that the following can stabilize the discharge and prevent the peeling of the deposited film, thereby improving the uniformity of the deposited film and suppressing the occurrence of image defects.
Further, as an optimal method, a technique of coating an alumina ceramic with a microwave introducing means by a plasma spraying method is mentioned.
With such a technique, it has become possible to form a high-quality deposited film with few spherical protrusions.
[0006]
[Problems to be solved by the invention]
However, in recent years, with the improvement in overall performance of devices using the above-described amorphous silicon material, demand for higher quality amorphous silicon material has been increasing.
Under these circumstances, there is currently room for improvement in devices using conventional amorphous silicon materials.
For example, in the field of electrophotography, in order to reduce service costs, it is necessary to reduce the number of maintenance operations by improving the reliability of each component.
Under these circumstances, the light receiving member for electrophotography can be used repeatedly for a longer time than before without maintenance by a service person in various environments.
For example, in a conventional deposited film forming apparatus, a "white spot" in which a minute white point occurs on a copy image, and a "black spot" in which a minute black point occurs, in some cases, occur.
In some cases, image density unevenness also occurs depending on conditions.
Such a defect on a copy image is such that as the speed of image formation is increased and the definition thereof is further advanced, a small defect of a deposited film and characteristic unevenness, which have not been a problem in the past, have remarkably appeared. .
[0007]
Therefore, the present invention solves the above-mentioned problems in the conventional art, prevents uneven distribution of high-frequency power into plasma, and makes uniform the plasma, thereby effectively suppressing the characteristic unevenness of the deposited film. It is an object to provide a deposited film forming apparatus and a deposited film forming method.
Further, the present invention provides a deposited film forming apparatus and a deposited film forming method capable of forming an electrophotographic light-receiving member in which uniform growth of deposited films is suppressed, abnormal growth is suppressed, and image defects such as white spots and black spots are suppressed. It is intended to provide a way.
[0008]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present invention is configured with a deposited film forming apparatus and a deposited film forming method as follows.
That is, in the deposition film forming apparatus of the present invention, a substrate is disposed in a reaction vessel capable of vacuum sealing, and a source gas is introduced into the reaction vessel by a source gas introduction unit, and high-frequency power is introduced by a high-frequency power introduction unit. In the deposited film forming apparatus for forming a deposited film on the substrate by the occurrence of a glow discharge by the high frequency power, the high frequency power introducing means uses an insulating material as a base material and is separated from the glow discharge region by the insulating material. In the set area, a metal material having a thickness sufficient to transmit the high-frequency power is formed in a shape that makes impedance discontinuous, and is formed in close contact with the insulating material. .
Further, in the method of forming a deposited film according to the present invention, the high-frequency power has a thickness sufficient to transmit the high-frequency power in a region separated from a glow discharge region by an insulating material, using an insulating material as a base material. Is formed by introducing a metal material having a shape having discontinuous impedance into a shape having discontinuous impedance and being brought into close contact with the insulating material, thereby forming a deposited film.
In the present invention, as the shape for making the impedance discontinuous, a shape in which the propagation path of the high-frequency power is partially branched into a plurality, or a shape in which a part of the propagation path of the high-frequency power is folded, Alternatively, it can be formed in a coil shape.
In the present invention, the insulating base material is preferably a ceramic material, and more preferably alumina ceramic.
In the present invention, the base is preferably a cylindrical base, and more preferably, a plurality of bases are arranged on the same circumference.
Also, in the present invention, the high-frequency introduction means is provided with a cooling mechanism or a heating mechanism.MoyoNo.
In the method for forming a deposited film according to the present invention, the high-frequency power has an optimal frequency in a range of 20 MHz to 450 MHz.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
In the present invention, by configuring the high-frequency introducing means as described above, the bias of the radiation of the high-frequency power can be prevented, and the uniformization of the plasma enables the growth process of the deposited film to be uniform. This makes it possible to essentially suppress characteristic unevenness.
Further, by suppressing peeling of the film from the surface of the high-frequency introducing means, it is possible to suppress the occurrence of spherical projections of the deposited film.
As described above, the present invention achieves a high level of both suppression of characteristic unevenness and suppression of occurrence of white spots or black spots due to film peeling, which were conventionally difficult to achieve at the same time. It has been completed based on the following circumstances.
[0010]
That is, the inventor paid attention to the form of the high-frequency wave introducing means and studied in order to solve the above-mentioned problems. As a result, the following findings were obtained regarding the causes of the occurrence of characteristic unevenness, white spots, and black spots.
1. About characteristic unevenness
It is considered that the cause of the characteristic unevenness is mainly the unevenness of the high frequency power emitted into the plasma from the high frequency introducing means.
In the conventional high-frequency introducing means, the high-frequency power tends to be strong at both ends of the high-frequency introducing means (substantially both ends of the portion that emits high-frequency power into the plasma) and to be weak near the center. This is considered to be due to interference that weakens near the center due to multiple reflections of high-frequency power generated on the surface of the high-frequency introducing means.
Such a tendency becomes more conspicuous, for example, as the frequency of the high frequency is increased for the purpose of increasing the formation speed of the deposited film. It is considered that this is because interference becomes more prominent when the wavelength of the high frequency wave approaches the length of the practical high frequency wave introducing means. When the high-frequency power is increased, the high-frequency power becomes saturated with respect to the raw material gas at both ends of the high-frequency introduction means, whereas the power at the center relatively increases, so that unevenness is reduced. Tend to be.
Such non-uniformities in high-frequency power are not large enough to affect the deposition rate of the film on the substrate, but are observed as differences in the saturated electron current in the plasma, and actually affect the characteristics of the deposited film. give.
In particular, it has been found that the difference appears as a slight difference in light sensitivity. For example, when viewed as a light receiving member for electrophotography, it has been found that the difference appears as unevenness on a halftone image.
2. About white poti
As described above, the cause of the white spots is abnormal growth of the deposited film called a spherical projection generated when a piece of the separated deposited film is taken into the deposited film.
Such a spherical projection often has a gap at the boundary with a normal deposited film, and the charge is lost due to the loss of charge through this gap, and appears as a white dot on a copy image.
In order to prevent the generation of the spherical projections, it is possible to coat alumina ceramics or the like by the plasma spraying method as described above.
However, even if such a coating is applied to the high-frequency wave introducing means, the effect is not always sufficient.
On the surface of the high-frequency introducing means, film deposition occurs under conditions where the temperature is higher than that of the normal substrate surface, and further, self-bias due to high-frequency power causes excessive ion bombardment. Film peeling occurs. Under these conditions, film peeling may occur even when the surface of the electrode is coated with, for example, alumina ceramics by plasma spraying.
On the other hand, if the roughness (surface roughness) of the surface of the electrode (the surface of the coating material) is increased to improve the adhesion of the deposited film, the adhesion of the film can be further improved. However, in the case of plasma spraying, if the particle size of the sprayed material is increased in order to increase the surface roughness, the porosity becomes extremely large, so that the binding force of the coating layer is reduced and the coating layer itself is peeled off, and instead, the white spots Was sometimes increased.
3. About Black Pot
The characteristic unevenness due to the unevenness of the high frequency power can be suppressed to some extent by increasing the high frequency power as described above.
However, it has been found that black spots often occur in the electrophotographic light receiving member in which the characteristic unevenness is prevented.
Observation of such an electrophotographic light-receiving member revealed that fine protrusions occurred on the surface of the deposited film.
In such a ridge, the diameter of the spherical projection causing white spots as described above is almost 10 μm or more, whereas the diameter of the spherical projection is 10 μm or less and there is no clear boundary like the spherical projection around the ridge. Is the feature. Therefore, since charging and discharging are performed in the same manner as in a portion where a normal film is deposited, it hardly appears as an image defect on an initial copy image.
However, when image formation is repeated at a high speed for a long period of time, the protrusion causes the fusion of the toner to occur, resulting in a black spot on the image.
Such a bulge tends to occur when an excessive amount of high-frequency power is applied during formation of the deposited film.
That is, it was found that when the high-frequency power was increased, it was likely to occur at the upper and lower portions of the electrophotographic light-receiving member. Therefore, it is presumed that the occurrence of the bulge is likely to occur due to excessive input of high frequency power.
From the above analysis, the present inventor has been studying high-frequency introducing means capable of achieving uniform radio-frequency power radiation. According to the knowledge of the present inventor, it is effective to make the impedance of the high frequency introducing means discontinuous in order to prevent the bias of the high frequency power.
In the case of such a structure, high-frequency power is reflected not only at both ends of the high-frequency introducing means but also at a discontinuous surface of impedance, and as a result, interference of power is disturbed and radiation becomes uniform.
However, even if an electrode having a discontinuous impedance configuration is installed in plasma as it is, the effect cannot be sufficiently obtained.
Although the cause is not clear, it is considered that when the electrode is directly exposed to the plasma, the impedance change surface is unlikely to act as a large reflection surface. Further, since the high-frequency introducing means having such a discontinuous impedance structure has a complicated shape, there is a problem that the deposited film is easily peeled off from the surface of the high-frequency introducing means during formation of the deposited film, and sparks are easily generated.
Furthermore, even if the electrode surface is coated with plasma spraying of alumina ceramics so that the electrode is not directly exposed to the plasma, the problems of peeling of the deposited film and sparking cannot be solved at the same time. This is because the greater the thickness of the coating layer, the greater the effect of preventing sparking, but the less the strength of the coating layer.
[0011]
In order to improve the above-mentioned problems such as characteristic unevenness, white spots, black spots, etc., a study was also made to provide a cover made of an insulating material for the high-frequency introducing means. However, the bias of the high-frequency power tended to increase in some cases.
This is considered to be due to a gap generated between the electrode that propagates the high frequency and the cover.
Although there are still many unclear points about the relationship between the non-uniformity of the characteristics and the electrode and the cover made of the ceramic material, the mechanism is presumed to be roughly as follows.
[0012]
Generally, transmission of high-frequency power is performed in a dielectric portion between conductors. In the case of a configuration like the deposited film generating apparatus of the present invention, it can be regarded as a coaxial structure with the electrode as the center and the cylindrical base as the outer conductor.
In this case, the space between the electrode and the cover made of the ceramic material is negligibly small with respect to the space between the base (external conductor) and the electrode (center conductor).
On the other hand, when a glow discharge occurs, the plasma is considered to act as a kind of conductor, so that the load impedance largely depends on the condition of the sheath region formed around the electrodes. In this case, the effect of the gap between the electrode and the cover made of the ceramic material cannot be ignored.
[0013]
Under such circumstances, the discharge is greatly affected by the fluctuation of the gap between the electrode and the cover made of the ceramic material.
For example, when the gap is not uniform due to a problem in machining, the discharge may be largely biased.
Further, when the temperature of the electrode rises during the glow discharge, the size of the gap changes due to the thermal expansion of the electrode, so that the matching condition may greatly change.
Such deviations and variations in the discharge not only lead to uneven characteristics of the light receiving member for electrophotography, but also cause deposition of an easily peelable film on the surface of the ceramic material cover, which may lead to generation of spherical projections.
Such a tendency tends to appear more remarkably as the high-frequency power or the frequency increases.
[0014]
It is practically difficult to eliminate the gap between the electrode and the cover as described above. For example, when thermal expansion occurs in the electrode, it is necessary to provide a certain gap due to the difference in the thermal expansion coefficient between the ceramic material and the electrode.
Regarding mechanical fitting, ceramic materials have low toughness compared to metal, and therefore, unless a certain amount of gap is provided, breakage often occurs.
Therefore, it is a design principle to set an appropriate gap between the electrode and the cover made of the ceramic material.
On the other hand, according to the study of the present inventor, the smaller the gap is, the more the unevenness of discharge tends to increase. Also, as the gap is increased, the loss of high frequency power increases.
[0015]
For the reasons described above, it is difficult for the mechanism of the conventional high-frequency introduction means to achieve both high-frequency power uniformity and prevention of peeling of the deposited film from the surface, that is, suppression of the occurrence of white spots and black spots. It has been difficult to achieve both uniformity of the characteristic unevenness of the light receiving member for electrophotography and a high level.
The present invention has been completed based on the above-described analysis, and has the following unique operation based on the configuration.
That is, in the high-frequency power introducing means used in the present invention, since the surface in contact with the plasma is covered with the insulator by the base material, the adhesion of the deposited film is good and the coating material does not peel off.
In addition, since the electrode is covered with an insulating material, the discontinuous surface of the impedance effectively acts as a reflection surface of the high-frequency power, so that the effect of homogenizing the high-frequency power is large, and the discontinuous surface of the impedance is provided. Spark generation can be effectively prevented even with a complicated electrode structure.
Further, since the electrodes are closely attached to the inside of the insulating material (the space separated from the discharge space by the insulating material), the unevenness of the high-frequency power due to the gap does not occur.
According to the present invention, as described above, the problems related to the above-mentioned amorphous silicon device can be effectively solved.
[0016]
Hereinafter, the contents of the present invention will be described in more detail.
The high-frequency introducing means used in the present invention has a configuration in which a metal material (electrode) capable of transmitting high-frequency power is formed in close contact with at least an insulator as a base material in a region separated from the glow discharge region by the insulator.
Examples of the insulator material used as the base material include glasses such as quartz glass and pyrex glass, alumina ceramics, titanium dioxide, aluminum nitride, boron nitride, zircon, cordierite, zircon cordierite, silicon oxide, beryllium oxide, and mica. Ceramics such as ceramics can be used, but ceramics are desirable from the viewpoint of durability and adhesion of the deposited film. Among them, alumina ceramics, in addition to the above-mentioned durability and good adhesion of the film, absorb high frequency power. Most suitable because there are few. The shape of the insulator and the electrode serving as the base material is desirably a cylindrical shape (or a columnar shape) in terms of workability, ease of forming the electrode, and the like.
Further, it is desirable that the insulators and the electrodes are arranged concentrically for the same reason.
Further, at least a surface of the insulator in contact with the discharge space may be provided with irregularities mainly for the purpose of preventing the deposited film from peeling off.
In this case, the size of the unevenness is preferably in a range of 5 μm or more and 200 μm or less in ten-point average roughness (Rz) with 2.5 mm as a reference length.
The means for providing irregularities on the surface is not particularly limited, but for example, blasting by spraying a projectile is practically preferable.
[0017]
There is no particular limitation on the size of the insulator serving as the base material.
However, when a plurality of cylindrical conductive substrates are arranged on the same circumference and the source gas introduction device and the electrode are installed within the circle where the cylindrical conductive substrates are arranged, the size of the cylindrical insulator ( That is, the diameter of the cylindrical or columnar high-frequency introducing means is preferably about 4 to 25% of the diameter of the circumference on which the base is arranged.
Although the thickness of the cylindrical insulator is not particularly limited, it is practically about 0.5 to 20 mm from the viewpoint of processing and mechanical strength.
Further, the diameter of the cylindrical (or cylindrical) electrode itself is not particularly limited as long as the diameter satisfies the diameter and thickness of the insulator described above. Practically, a diameter of 2 mm or more is desirable.
The length of the high frequency introducing means is desirably in the range of about 100 to 150% of the length of the base.
However, even if the length is less than 100% with respect to the substrate, there is no problem in obtaining the effects of the present invention.
Here, the length of the high-frequency introducing means refers to a portion having a function of radiating a high frequency substantially in the discharge space.
[0018]
As the material of the electrode, any material can be used as long as it is conductive, but metals such as Al, Cr, Cu, Mo, Au, Ag, In, Nb, Ni, Te, V, Ti, Pt, Pb, and Fe In addition, alloys of these materials, for example, stainless steel, Inconel, Hastelloy and the like can be used.
The thickness of the electrode may be any thickness as long as high-frequency power can be transmitted. That is, the thickness may be any thickness that is equal to or greater than the skin effect determined by the frequency of the high-frequency power used and the material of the electrodes.
For example, when the frequency of the high-frequency power is 105 MHz and the material of the electrode is Cu (copper), the notation effect is about 7 μm. Therefore, in this case, the thickness of the electrode may be 7 μm or more.
On the other hand, when the temperature rise of the electrode is large, if the thickness of the electrode is large, the electrode may be peeled off due to the difference in the coefficient of thermal expansion of the insulator serving as the base material.
Therefore, it is desirable that the upper limit of the electrode thickness be determined by the conditions at the time of forming the deposited film.
[0019]
Any method of forming an electrode in close contact with an insulating material can be used in the present invention. For example, a chemical plating method, a thermal spraying method, a sputtering method, brazing, a solid diffusion bonding method, or the like is used.
Any method of forming a pattern that makes impedance discontinuous on the electrode is effective for the present invention.
For example, a method of changing the shape such as a method of branching a part of the electrode into a plurality of parts, a method of folding a part of the electrode, and a method of forming a coil is used.
In any case, the effect of the present invention can be obtained if a discontinuous surface of impedance is formed.
The positions of the discontinuity planes of these impedances are appropriately selected according to the conditions at the time of forming the deposited film so that the radiation of the high-frequency power becomes the most uniform.
[0020]
A cavity is formed inside the high frequency introducing means (that is, on the side separated from the glow discharge region) by a combination of the size (diameter), thickness, and electrode thickness of the insulator. This cavity may be maintained in a vacuum or separated from the vacuum system by a vacuum seal.
In any case, it is desirable to prevent the raw material gas from flowing into the inside in order to avoid stagnation of the raw material gas.
The cavities can also be filled with padding. In this case, as the filling material, a synthetic resin such as polycarbonate, Teflon, polyamide, or polyimide can be used in addition to the insulating material serving as the insulator material serving as the base material of the high-frequency introducing means. These fillers may adhere to the cavity-side surface of the electrode or may have a gap.
In particular, when thermal expansion or the like becomes a problem, an appropriate gap (about 0.1 mm to 5 mm) can be provided.
Also in this case, since the high-frequency power is mainly radiated into the plasma from the portion facing the discharge region, the effect of this gap was hardly observed.
[0021]
The number of high frequency introducing means may be one or a plurality. In the case where the number of the high-frequency introducing means is one, it is desirable to be coaxial with the center of the arrangement circle of the cylindrical conductive substrate from the viewpoint of ensuring uniformity.
When a plurality of high frequency introducing means are provided, it is desirable that each of the high frequency introducing means is arranged on a circumference concentric with the arrangement circle of the base. The arrangement circle of the high-frequency introducing means may be smaller or larger than the arrangement circle of the cylindrical conductive substrate.
That is, a plurality of high-frequency introducing means may be arranged concentrically inside the arrangement circle of the cylindrical conductive substrate, or may be arranged concentrically outside the arrangement circle of the cylindrical conductive substrate.
When the plurality of high-frequency introducing means are arranged concentrically outside the circle where the cylindrical conductive substrate is arranged, at least one high-frequency introducing means is arranged inside the circle where the cylindrical conductive substrate is arranged. It is desirable.
When two high-frequency introducing means are provided, the high-frequency introducing means may be divided into two in the generatrix direction (drawing direction).
In this case, the position of the high frequency introducing means is desirably set at the center of the arrangement circle of the base as described above. In each case, each high-frequency introducing means is arranged in the arrangement circle of the base. Further, in the present invention, a means for heating or cooling the high frequency introducing means may be provided.
In this case, by controlling the high frequency introducing means to a desired temperature, the adhesion between the insulator serving as the base material and the deposited film is improved, and the occurrence of film peeling can be more effectively prevented. Whether the high-frequency introducing means is cooled or heated is determined by the combination of the deposited film material and the insulating material serving as a base material, the high-frequency power, the pressure, the flow rate of the source gas, and the like.
Further, in the present invention, the high frequency introducing means and the raw material gas introducing means can also be used.
In this case, it is preferable that the source gas is discharged into the discharge space through a gas discharge hole formed in the insulator through a flow path of the source gas formed inside the insulator.
[0022]
In the present invention, the source gas is decomposed by applying high-frequency power to the high-frequency introducing means.
The frequency of the high-frequency power that can be used in the present invention is not particularly limited. However, according to experiments performed by the inventor, when the frequency is less than 20 MHz, discharge becomes unstable depending on conditions, and the conditions for forming a deposited film are limited. There was a case.
If the frequency is higher than 450 MHz, the transmission characteristics of high-frequency power deteriorate, and in some cases, it is difficult to generate glow discharge itself.
Therefore, a frequency range of 20 MHz to 450 MHz is optimal for the present invention.
Any high-frequency waveform may be used, but a sine wave, a rectangular wave, or the like is suitable.
The magnitude of the high-frequency power is appropriately determined depending on the characteristics of the target deposited film and the like, but is preferably from 10 to 5000 W, more preferably from 20 to 2000 W per substrate.
[0023]
Hereinafter, the deposited film forming apparatus of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic view showing an example of a high-frequency introducing means used in the present invention, in which a part of an electrode is branched into a plurality of parts to make impedance discontinuous. In the example of FIG. 1, the high frequency introducing means 102 includes a cylindrical insulator 111 and an electrode 112.
The outside of the insulator 111 is a glow discharge region, and the inside is a region separated from the glow discharge region.
The electrode 112 is formed in close contact with the inner surface of the insulator 111 (that is, the surface on the side of the region separated from the glow discharge region).
A cavity 113 is formed inside the high-frequency introducing means (further inside the electrode), is separated from the vacuum system by a vacuum seal (not shown), and has a structure in which the source gas does not flow.
The electrode 112 is connected to a high-frequency introduction terminal (not shown) at the upper part, and high-frequency power is applied from a high-frequency transmission circuit (not shown).
[0024]
In the example of FIG. 1, the electrode 112 is branched into two paths inside the insulator 111. In this example, the impedance is discontinuous in each of three regions A, B, and C in the figure.
FIG. 2 is a schematic diagram of an example of the high-frequency introducing means used in the present invention in which the impedance is discontinuous by folding a part of the electrode.
FIG. 3 is a schematic diagram of an example of the high-frequency introducing means used in the present invention in which impedance is discontinuous by forming a part of the electrode in a coil shape.
2 and 3, the impedance is discontinuous in three regions A, B, and C, respectively.
FIG. 4 is a schematic view illustrating a cylindrical high-frequency introducing means used in the present invention when a cooling mechanism is provided.
[0025]
In the example of FIG. 4, an electrode 112 is formed in close contact with a cylindrical insulator 111 and an inner surface of the insulator, and a cavity 113 is formed further inside. The electrode 112 is branched into two paths inside the insulator, forming a discontinuous surface of impedance. The cavity is separated from the vacuum system by a vacuum seal (not shown), and a coolant inlet 119 and a coolant outlet 121 for cooling are provided at an upper portion, and a coolant inlet pipe 120 is provided inside.
In the example of FIG. 4, the refrigerant supplied from the refrigerant supply device (not shown) is introduced into the cavity 113 from the refrigerant supply port 119 through the refrigerant introduction pipe 120, directly cools the electrode 112, and then flows from the refrigerant discharge port 121. Is discharged.
[0026]
FIGS. 5A and 5B are schematic diagrams of an example of a deposited film forming apparatus of the present invention in a case where a plurality of cylindrical conductive substrates are arranged on the same circumference.
This apparatus is roughly classified into a reaction vessel 100, a raw material gas supply device (not shown), an exhaust device (not shown) for reducing the pressure inside the reaction vessel 100, and a power supply for supplying power to the high-frequency introduction means 102. It comprises a power supply 107.
In a reaction vessel 100, a cylindrical conductive substrate 101, a substrate heating heater 104,High frequency introduction means102 is installed,High frequency introduction meansIs connected to a power supply 107 via a high-frequency matching box 106.
The base 101 is held on a rotating shaft 108 via a holder (not shown). The rotating shaft 108 penetrates through a vacuum seal (not shown) to the atmosphere side of the reaction vessel 100, and a motor 109 through a gear 110. It is connected to the.
In the glow discharge region 103, a source gas introduction unit 105 is arranged and connected to a source gas supply device (not shown).
[0027]
The bases 101 are arranged on the same circumference, and a glow discharge region 103 is formed in a region surrounded by the bases.
The number of bases may be any number as long as it can form a discharge space, but is preferably four or more. FIG. 5 shows an example in which eight bases are arranged.
The number of the raw material gas introduction means 105 may be any number. However, when the number is one or the same as the number of the bases, or when the number of the bases is an even number, a half of the number of the bases is suitable..
BaseThe body 101 is heated from the inside by a substrate heating heater 104 installed in the reaction vessel 100.
The substrate heating heater 104 may be of any type as long as it has a vacuum specification. For example, a sheath heater wound around a pipe, an electric resistor such as a plate heater or a ceramic heater, or a heat radiator such as a halogen lamp may be used. Heat exchange means mediated by gas or liquidByHeating elements can be used.
[0028]
In addition, these substrate heating heaters are provided in the reaction container 100. In addition, a substrate heating container is provided separately from the reaction container, and is installed therein. Means for transporting the substrate in a vacuum to 100 may be employed. Further, the heating of the substrate by the substrate heating container and the heating of the substrate in the reaction container 100 can be used in combination.
The temperature of the substrate is appropriately selected in an optimum range depending on the desired properties of the deposited film, but is usually preferably 20 to 500 ° C, more preferably 50 to 480 ° C, and most preferably 100 to 450 ° C. Is desirable.
[0029]
Next, a procedure of forming a deposited film using the apparatus of FIG. 5 will be described.
The formation of a deposited film using this apparatus can be performed, for example, as follows.
First, the substrate 101 degreased and washed in advance is set in the reaction vessel 100, and the inside of the reaction vessel 100 is evacuated by an exhaust device (not shown) (for example, a vacuum pump).
Subsequently, while rotating the base 101, the temperature of the base 101 is controlled to a desired temperature of 20 ° C. to 500 ° C. by the heater 104.
When the temperature of the base 101 reaches a desired temperature, a source gas is supplied from a source gas supply system (not shown) to a source gas supply pipe.105ThroughReaction vessel 100Supply within. At this time, care should be taken not to cause extreme pressure fluctuation such as gas projection. Next, when the flow rate of the source gas reaches a predetermined flow rate, an exhaust valve (not shown) is adjusted while watching a vacuum gauge (not shown) to obtain a desired internal pressure.
[0030]
When the internal pressure is stabilized, the high-frequency power source 107 is set to a desired power, andIntroduction methodHigh-frequency power is applied to 102 to cause glow discharge.
The source gas introduced into the reaction vessel 100 is decomposed by the discharge energy, and a predetermined deposited film is formed on the base 101.
At this time, by rotating the base 101 by the motor 109 during formation of the deposited film, the deposited film is formed on the entire surface of the base.
After the formation of the desired film thickness, the supply of the high-frequency power is stopped, the flow of the source gas into the reaction vessel is stopped, and the formation of the deposited film is completed.
When a deposited film composed of a plurality of layers is formed on a substrate due to the desired properties of the deposited film, a deposited film having a desired layer configuration can be obtained by repeating the above operation.
[0031]
In the present invention, a cylindrical substrate is used as the substrate, and as the material, a conductive material or a material whose surface is subjected to conductive treatment is usually used.
For example, metals such as Al, Cr, Mo, Au, In, Nb, Ni, Te, V, Ti, Pt, Pb, and Fe, and alloys thereof can be used.
Examples of materials whose surfaces are conductively treated include alumina ceramics, aluminum nitride, boron nitride, silicon nitride, silicon carbide, silicon oxide, beryllium oxide, quartz glass, pyrex glass, and the like, as well as polycarbonate, polyamide, polyimide, and Teflon. Synthetic resins can be used.
When a material whose surface has been subjected to conductive treatment is used as a substrate, it is desirable to conduct conductive treatment also on the side opposite to the side on which the deposited film is formed.
[0032]
As the source gas used in the present invention, for example, in the case of forming amorphous silicon, silicon hydride (silanes) in a gas state such as SiH4 or Si2H6 or gasifiable silicon is effectively used as a Si supply gas. You.
In addition to silicon hydride, a silicon compound containing a fluorine atom, a so-called silane derivative substituted with a fluorine atom, specifically, for example, silicon fluoride such as SiF4, Si2F6, or SiH3F, SiH2F2, SiHF3, or the like. A gaseous or gasifiable substance such as fluorine-substituted silicon hydride is also effective as the Si supply gas of the present invention.
Further, the present invention can be used without any problem even if the raw material gas for supplying Si is diluted with a gas such as H2, He, Ar, or Ne as necessary.
Further, in addition to the above-mentioned gas, an atom belonging to Group 3 of the periodic table or an atom belonging to Group 5 of the periodic table can be used as a so-called dopant, if necessary. For example, when a boron atom (B) is used, boron hydride such as B2H6 and B4H10, and boron halide such as BF3 and BCl3 can be used. When a phosphorus atom is used, a hydrogenated phosphorus such as PH3 or P2H4 can be used.
[0033]
For example, in the case of forming amorphous silicon carbide (a-SiC), in addition to the above-mentioned raw material gas, as a gas for introducing carbon atoms, C and H are used as constituent atoms. Saturated hydrocarbons having 5 carbon atoms, ethylene hydrocarbons having 2 to 4 carbon atoms, acetylene hydrocarbons having 2 to 3 carbon atoms, and the like can be used.
Specifically, methane (CH4), ethane (C2H6) or the like as a saturated hydrocarbon, ethylene (C2H4) or propylene (C3H6) as an ethylene-based hydrocarbon, and acetylene (C2H2) as an acetylene-based hydrocarbon. ), Methylacetylene (C3H4) and the like.
When amorphous silicon oxide (a-SiO) is formed, for example, oxygen (O2), ozone (O3), monoxide may be used as a gas for introducing oxygen atoms in addition to the above-mentioned source gas. Nitrogen (NO), nitrogen dioxide (NO2), nitrogen monoxide (N2O), nitrogen trioxide (N2O3), nitrogen tetroxide (N2O4), nitrogen pentoxide (N2O5), nitrogen trioxide (NO3), silicon atom (Si ), An oxygen atom (O) and a hydrogen atom (H) as constituent atoms, for example, lower siloxanes such as disiloxane (H3SiOSiH3) and trisiloxane (H3SiOSiH2OSiH3).
[0034]
In the present invention, for example, when forming amorphous silicon nitride (a-SiN), nitrogen (N2), ammonia (NH3), Examples include gaseous or gasifiable nitrogen such as hydrazine (H 2 NNH 2) and hydrogen azide (HN 3), and nitrogen compounds such as nitrogen and azide.
In addition to these, nitrogen halide compounds such as nitrogen trifluoride (F3N) and nitrogen tetrafluoride (F4N2) can be given because halogen atoms can be supplied in addition to nitrogen atoms.
Similarly, the gas pressure in the reaction vessel is appropriately selected in an optimum range depending on the intended properties of the deposited film, but is usually 0.01 to 1000 Pa, preferably 0.03 to 300 Pa, and most preferably 0 to 1000 Pa. .1 to 100 Pa is preferable.
[0035]
【Example】
Hereinafter, Experimental Example 1 and Examples of the present invention will be described, but the present invention is not limited thereto.
[0036]
(Experimental example 1)
The high frequency introducing means of the present invention shown in FIG. 1 was installed in the deposited film forming apparatus shown in FIG. 5, and the bias of plasma was examined by measuring a saturated electron current using a single probe (Langmuir probe). In this experimental example, the length of the high frequency introducing means was 420 mm, and the material of the insulator serving as the base material was alumina ceramics. The single probe was configured to be movable in a vacuum, and the saturation electron current was measured every 20 mm in the generatrix direction of the high-frequency introducing means. Table 1 shows the discharge conditions at this time.
[0037]
[Table 1]

FIG. 6 shows the distribution of the measured electron temperatures. In FIG. 6, the value of the saturated electron current is shown as being normalized with the largest value being 1. As is clear from FIG. 6, no bias of the discharge was observed in the high frequency introducing means of the present invention.
[0038]
<Comparative experiment example 1>
The conventional high frequency introducing means was installed in the deposited film forming apparatus shown in FIG. 5, and the bias of the plasma was measured in the same manner as in Experimental Example 1. The high-frequency introducing means used in the present experimental example has a metal column made of metal and has no impedance discontinuity surface. Note that the diameter of the electrode is the same as the outer diameter of the electrode used in Experimental Example 1 (the inner diameter of the insulator), and the same overall length.
FIG. 7 shows the result of the measurement. In FIG. 7, the value of the saturated electron current is standardized assuming that the largest value is 1, as in the case of Experimental Example 1. As is clear from the results of FIG. 7, the bias of the plasma was observed in the conventional high-frequency introducing means.
[0039]
<Comparative experiment example 2>
In the deposited film forming apparatus shown in FIG. 5, a conventional high-frequency introducing means in which an electrode was not provided with an insulator cover (the electrode surface was exposed to plasma) was installed, and the bias of plasma was measured in the same manner as in Experimental Example 1. . As the high-frequency introducing means used in this experimental example, an electrode was used in which an electrode formed a discontinuous surface having the same impedance as the high-frequency introducing means used in Experimental Example 1. FIG. 8 shows the result of the measurement. In FIG. 8, the value of the saturated electron current is standardized assuming that the largest value is 1, as in the case of Experimental Example 1. As is apparent from the results of FIG. 8, the bias of the plasma was observed in the conventional high-frequency introducing means.
[0040]
<Comparative experiment example 3>
The conventional high frequency introducing means was installed in the deposited film forming apparatus shown in FIG. 5, and the bias of the plasma was measured in the same manner as in Experimental Example 1. The high-frequency introducing means used in the present experimental example was such that an electrode was formed with an insulating cover on the electrode in which a discontinuous surface having exactly the same impedance as the high-frequency introducing means used in Experimental Example 1 was formed. The gap between the cover and the electrode was about 0.5 mm. FIG. 9 shows the measurement results. In FIG. 9, the value of the saturated electron current is standardized assuming that the largest value is 1, as in the case of Experimental Example 1. As is apparent from the results of FIG. 9, the bias of the plasma was observed in the conventional high-frequency introducing means.
[0041]
(Experimental example 2)
The high-frequency introducing means of the present invention shown in FIG. 1 is installed in the deposition film forming apparatus shown in FIG. 5, and a charge injection blocking layer 1003, a photoconductive layer 1004, and a surface layer 1005 are formed on a substrate 1002 as shown in FIG. An electrophotographic light-receiving member 1001 having a layer structure sequentially laminated was prepared. The discharge conditions are shown in Table 2 below.
[0042]
[Table 2]

The "layer thickness" in Table 2 above is a rough guide in designing a light receiving member for electrophotography.
[0043]
In this experimental example, the material of the insulator serving as the base material was alumina ceramics, and the surface roughness on the glow discharge region side (10-point average roughness with 2.5 mm as a reference length) was changed from about 1 μm to about 200 μm. . The number of spherical protrusions was evaluated for the light receiving member for electrophotography thus produced. The number of spherical projections was evaluated as follows. The surface of each electrophotographic light-receiving member was observed with an optical microscope, and the number of spherical projections having a diameter of 10 μm or more per 10 cm 2 was examined. Regarding the number of spherical projections, a value obtained by measuring all eight electrophotographic light-receiving members formed at the same time and then averaging the whole was adopted.
[0044]
<Comparative experiment example 4>
Using a conventional electrode obtained by plasma spraying alumina ceramics on the electrode surface in the deposition film forming apparatus shown in FIG. 5, the surface roughness was changed from about 1 μm to about 200 μm. It was created.
The number of spherical projections of the electrophotographic light-receiving member thus produced was evaluated in the same manner as in Experimental Example 2.
[0045]
<Comparative Experimental Example 5>
In the deposition film forming apparatus shown in FIG. 5, the surface of the electrode was not provided with an insulator (only a metal electrode), and the surface roughness was changed from about 1 μm to about 200 μm using a conventional electrode. An electrophotographic light-receiving member was prepared. The number of spherical projections of the electrophotographic light-receiving member thus produced was evaluated in the same manner as in Experimental Example 2.
FIG. 11 shows the results of Experimental Example 2 and Comparative Experimental Examples 4 and 5 together. In FIG. 11, the value of the spherical projection is expressed by relative evaluation, assuming that the value at the surface roughness of about 28 μm in Experimental Example 2 is 1. According to FIG. 11, the roughening of the surface of each electrode tends to suppress film peeling and reduce the number of spherical projections. It was effective for prevention, and good results were obtained in each case. On the other hand, in the high-frequency introduction means (plasma sprayed alumina ceramics) of Comparative Experimental Example 4, when the surface roughness is increased, the spherical projections are reduced to a certain degree, but the spherical projections are increased when the surface roughness is further increased. Tend. This is presumably because the bonding strength of the thermal spray was weakened and the thermal spray itself peeled off.
In Comparative Examples 4 and 5, sparks were observed during discharge.
[0046]
(Experimental example 3)
The high-frequency introducing means of the present invention shown in FIG. 1 is installed in the deposition film forming apparatus shown in FIG. 5, and a charge injection blocking layer 1003, a photoconductive layer 1004, and a surface layer 1005 are formed on a substrate 1002 as shown in FIG. An electrophotographic light-receiving member 1001 having a layer structure sequentially laminated was prepared. Note that titanium dioxide was used as the material of the insulator serving as the base material of the high-frequency introducing means. In this experimental example, the power was changed at a high frequency of 105 MHz in the photoconductive layer to form an electrophotographic light receiving member. The discharge conditions are shown in Table 3 below.
[0047]
[Table 3]

The "layer thickness" in Table 3 above is a rough guide in designing a light receiving member for electrophotography.
The light receiving member for electrophotography thus prepared was evaluated for image density unevenness, the number of spherical projections, and black spots. The number of spherical projections was evaluated in the same manner as in Experimental Example 2, and image density unevenness and black spots were evaluated in the following manner.
(1) Image density unevenness
Each of the electrophotographic light-receiving members is set in an electrophotographic apparatus (a Canon NP6060 modified for this test), and a Canon halftone chart (part number: FY9-9042) is placed on a document table and copied. The image densities at arbitrary 50 points on the copy image obtained at the time of the above were measured with a reflection densitometer, and the ratio of the lightest image density portion to the darkest image density portion for each electrophotographic light-receiving member was calculated. The above measurements were made for all eight electrophotographic light-receiving members that were calculated and produced at the same time, and finally the average of the ratios was compared as image density unevenness.
(2) Black pot
Each of the electrophotographic light receiving members was set in an electrophotographic apparatus (a NP6060 manufactured by Canon Inc. modified for this test), and a halftone chart (part number: FY9-9042) manufactured by Canon was placed on a document table. Image formation of 3 million sheets was repeated using copy paper of the same size. A blank sheet was placed on a platen every 10,000 sheets on the way, and a black spot on a copy image obtained was inspected. In the evaluation, the following four-stage evaluation was used.
◎ Extremely good
○ good
△ No problem in practical use
× There is a problem
Table 4 shows the above results.
[0048]
[Table 4]

In Table 4, the image density unevenness and the spherical protrusion were each expressed by relative evaluation with the value of 1 when the high frequency power was 1500 W. From the results in Table 4, in the deposited film forming apparatus of the present invention, good results were obtained for all items in the figure.
[0049]
<Comparative experiment example 6>
An electrophotographic light-receiving member was prepared in the same manner as in Experimental Example 3, except that an electrode having no discontinuous impedance pattern was used in the deposited film forming apparatus shown in FIG. The light receiving member for electrophotography thus produced was evaluated for image density unevenness, the number of spherical projections, and black spots in the same manner as in Experimental Example 3. Table 5 shows the results.
[0050]
[Table 5]

In Table 5, the image density unevenness and the spherical protrusion were expressed as relative evaluations with the high-frequency power of 1500 W in Experimental Example 3 as 1. In the high-frequency introducing means used in this comparative example, as the high-frequency power is increased, the image density unevenness is improved, while the black spots are deteriorated. This is presumably because high-frequency radiation is partially concentrated, so that high-frequency power is partially concentrated, which affects film growth.
[0051]
<Comparative Experimental Example 7>
An electrophotographic light receiving member was used in the same manner as in Experimental Example 3, except that the electrode surface was not provided with an insulator coating (only metal electrodes) in the deposited film forming apparatus shown in FIG. It was created. The light receiving member for electrophotography thus produced was evaluated for image density unevenness, the number of spherical projections, and black spots in the same manner as in Experimental Example 3. Table 6 shows the results.
[0052]
[Table 6]

In Table 6, the image density unevenness and the spherical projection were expressed by relative evaluation, assuming that the high-frequency power of 1500 W in Experimental Example 3 was 1. From the results shown in Table 6, the effect of the discontinuity surface of the impedance was not so much obtained in the high frequency introducing means used in the comparative experimental example as compared with the high frequency introducing means of the present invention used in Experimental Example 3. In addition, many spherical projections were generated mainly due to the effect of peeling of the deposited film from the high frequency introducing means.
[0053]
(Experimental example 4)
The high-frequency introducing means of the present invention shown in FIG. 1 is installed in the deposition film forming apparatus shown in FIG. 5, and a charge injection blocking layer 1003, a photoconductive layer 1004, and a surface layer 1005 are formed on a substrate 1002 as shown in FIG. An electrophotographic light-receiving member 1001 having a layer structure sequentially laminated was prepared. The insulator used as the base material of the high frequency introducing means was aluminum nitride. In this experimental example, the light receiving member for electrophotography was formed by changing the frequency of the high frequency power. The discharge conditions are shown in Table 7 below.
[0054]
[Table 7]

The "layer thickness" in Table 7 above is a rough guide in designing a light-receiving member for electrophotography.
The light receiving member for electrophotography thus prepared was evaluated for image density unevenness, the number of spherical projections, and black spots. Table 8 shows the results.
[0055]
[Table 8]

X in Table 8 indicates that the discharge could not be stably maintained under these conditions, and the light receiving member for electrophotography could not be formed. From the results in Table 8, very good results were obtained for all items in the frequency range of 20 MHz to 450 MHz. On the other hand, when the frequency was set to 800 MHz, the discharge was maintained, but the high-frequency matching condition was not stabilized, resulting in a large image density unevenness.
[0056]
[Example 1]
The high frequency introducing means of the present invention shown in FIG. 1 was installed in the deposited film forming apparatus shown in FIG. 5, and a light receiving member for electrophotography having the layer constitution shown in FIG. 10 was produced. In this embodiment, alumina ceramics was used as the material of the insulator serving as the base material of the high frequency introducing means. Table 9 shows the discharge conditions.
[0057]
[Table 9]

The "layer thickness" in Table 9 above is a rough guide in designing a light-receiving member for electrophotography. The light receiving member for electrophotography thus prepared was evaluated with respect to the number of spherical projections, thickness unevenness, and image density unevenness.
[0058]
[Example 2]
The high frequency introducing means of the present invention shown in FIG. 2 was installed in the deposited film forming apparatus shown in FIG. 5, and a light receiving member for electrophotography having the layer constitution shown in FIG. 10 was produced. In this embodiment, alumina ceramics was used as the material of the insulator serving as the base material of the high frequency introducing means. Table 10 shows the discharge conditions.
[0059]
[Table 10]

The "layer thickness" in Table 11 above is a rough guide in designing a light receiving member for electrophotography. The light receiving member for electrophotography thus prepared was evaluated with respect to the number of spherical projections, thickness unevenness, and image density unevenness.
[0060]
[Example 3]
The high frequency introducing means of the present invention shown in FIG. 3 was installed in the deposited film forming apparatus shown in FIG. 5, and a light receiving member for electrophotography having the layer constitution shown in FIG. 10 was produced. In the present embodiment, titanium dioxide was used as the material of the insulator serving as the base material of the high frequency introducing means. Table 11 shows the discharge conditions.
[0061]
[Table 11]

The "layer thickness" in Table 11 above is a rough guide in designing a light receiving member for electrophotography. The light receiving member for electrophotography thus prepared was evaluated with respect to the number of spherical projections, thickness unevenness, and image density unevenness.
[0062]
[Example 4]
The high frequency introducing means of the present invention shown in FIG. 4 was installed in the deposited film forming apparatus shown in FIG. 5, and a light receiving member for electrophotography having the layer constitution shown in FIG. 10 was produced. In this embodiment, alumina ceramics was used as the material of the insulator serving as the base material of the high frequency introducing means. Table 12 shows the discharge conditions.
[0063]
[Table 12]

The "layer thickness" in Table 12 above is a rough guide in designing a light receiving member for electrophotography. The light receiving member for electrophotography thus prepared was evaluated with respect to the number of spherical projections, thickness unevenness, and image density unevenness.
[0064]
[Example 5]
The high frequency introducing means of the present invention shown in FIG. 4 was installed in the deposited film forming apparatus shown in FIG. 12, and a light receiving member for electrophotography having the layer constitution shown in FIG. 10 was produced. In this embodiment, alumina ceramics was used as the material of the insulator serving as the base material of the high frequency introducing means. In the apparatus shown in FIG. 12, eight high-frequency introducing means 102 are provided outside the circle where the base 101 is arranged and one is installed inside the circle where the base 101 is arranged. Each high frequency introducing means 102 is connected to a high frequency power supply (not shown) via a matching box 106. In the example of FIG. 12, since the glow discharge spreads uniformly inside and outside the arrangement circle of the base, a rotating mechanism of the base 101 as in the apparatus of FIG. 5 is not necessarily required. In the apparatus shown in FIG. 12, the base 101 is fixed to the support shaft 122.
Table 13 shows the conditions for preparing a light receiving member for electrophotography using the apparatus shown in FIG.
[0065]
[Table 13]

The "layer thickness" in Table 13 above is a rough guide in designing a light-receiving member for electrophotography. The light receiving member for electrophotography thus prepared was evaluated with respect to the number of spherical projections, thickness unevenness, and image density unevenness.
Table 14 summarizes the results of Examples 1 to 5 described above.
[0066]
[Table 14]

In Table 14 above, the number of spherical protrusions and the image density unevenness are shown by relative evaluation, with the value of Example 1 being set to 1. As is clear from Table 14, in the deposited film forming apparatus of the present invention, good characteristics were obtained in all cases.
[0067]
【The invention's effect】
As described above, according to the present invention, since the high-frequency power introducing means has a surface in contact with plasma covered with an insulator by a base material, the adhesion of the deposited film is good and the coating material does not peel off. In addition, since the electrodes are covered with an insulating material, the discontinuous surface of the impedance effectively acts as a reflection surface of the high-frequency power, and the uniformity of the high-frequency power can be achieved. Even with a complicated electrode structure, generation of sparks can be effectively prevented. Furthermore, since the electrode is formed in close contact with the inside of the insulating material, it is possible to prevent the occurrence of unevenness in high-frequency power due to the gap between the electrode and the insulating material.
[0068]
Therefore, according to the present invention, the occurrence of spherical projections, uneven image density, and the occurrence of black spots, which are problems in producing a light receiving member for electrophotography, are effectively suppressed, and extremely high quality electrophotographic light is obtained. A receiving member can be formed.
[Brief description of the drawings]
FIG. 1 is a schematic view showing an example of a high-frequency introducing means in which a part of an electrode of the present invention is branched into a plurality of parts to make impedance discontinuous.
FIG. 2 is a schematic view showing an example of a high-frequency wave introducing unit in which impedance is discontinuous by folding a part of an electrode of the present invention.
FIG. 3 is a schematic diagram showing an example of a high-frequency introducing means in which impedance is discontinuous by making a part of an electrode of the present invention into a coil shape.
FIG. 4 is a schematic view showing an example of a high-frequency introducing means provided with a cooling mechanism of the present invention.
FIG. 5 is a schematic view showing an example of a deposited film forming apparatus in which a cylindrical substrate of the present invention is arranged on the same circumference.
FIG. 6 is a graph showing a distribution of a saturated electron current in the deposited film forming apparatus of the present invention in Experimental Example 1.
FIG. 7 is a graph showing a distribution of a saturated electron current in Comparative Experimental Example 1.
FIG. 8 is a graph showing a distribution of a saturated electron current in Comparative Experimental Example 2.
FIG. 9 is a graph showing a distribution of a saturated electron current in Comparative Experimental Example 3.
FIG. 10 is a schematic cross-sectional view showing an example of a layer configuration of an electrophotographic light-receiving member prepared in each of the examples and the like.
FIG. 11 is a graph showing the number of spherical protrusions in Experimental Example 2 and Comparative Experimental Examples 4 and 5.
FIG. 12 is a schematic view showing one example of a deposited film forming apparatus of the present invention.
[Explanation of symbols]
100: reaction vessel
101: Substrate
102: High frequency introduction means
103: glow discharge area
104: heater for heating the substrate
105: Source gas introduction means
106: High frequency matching box
107: Power supply
108: Rotation axis
109: Motor
110: Gear
111: Insulator
112: electrode
113: Cavity
119: Refrigerant supply port
120: refrigerant introduction pipe
121: Refrigerant outlet
122: support shaft
1001: Light receiving member for electrophotography
1002: Substrate
1003: charge injection blocking layer
1004: Photoconductive layer
1005: surface layer

Claims (14)

A substrate is placed in a vacuum-tight sealable reaction vessel, a source gas is introduced into the reaction vessel by a source gas introduction unit, and a high-frequency power is introduced by a high-frequency power introduction unit. In a deposited film forming apparatus for forming a deposited film on the substrate,
The high-frequency power introducing means includes a metal material having a thickness sufficient for transmitting the high-frequency power in a region separated from the glow discharge region by the insulating material, using an insulating material as a base material. An apparatus for forming a deposited film, wherein the apparatus is formed in a continuous shape and is in close contact with the insulating material. 2. The deposition film forming apparatus according to claim 1, wherein a shape for making the impedance discontinuous is a shape in which a high-frequency power propagation path is partially branched. 2. The deposition film forming apparatus according to claim 1, wherein the shape for making the impedance discontinuous is a shape in which a part of a high-frequency power propagation path is folded back. 3. The deposition film forming apparatus according to claim 1, wherein the shape for making the impedance discontinuous is a coil shape. The apparatus according to claim 1, wherein the insulating base material is a ceramic material. The deposition film forming apparatus according to any one of claims 1 to 5, wherein the insulating base material is an alumina ceramic. The substrate, comprising a plurality of cylindrical substrates, wherein the plurality of cylindrical substrates are arranged on the same circumference so as to surround a film forming space in the reaction vessel. An apparatus for forming a deposited film according to claim 6. The deposition film forming apparatus according to claim 1, wherein the high-frequency introduction unit includes a cooling mechanism or a heating mechanism. A method for forming a deposited film on a substrate by disposing a substrate in a reaction container capable of vacuum sealing, introducing a source gas and high-frequency power into the reaction container, and generating a glow discharge by the high-frequency power At
The high-frequency power is made of an insulating material as a base material, and in a region separated from the glow discharge region by the insulating material, a metal material having a thickness sufficient to transmit the high-frequency power is discontinuously changed in impedance. A method for forming a deposited film, wherein the deposited film is formed by applying a high-frequency power introducing means which is formed into a shape which is in close contact with the insulating material. The method according to claim 9 , wherein the high frequency power has a frequency in a range of 20 MHz to 450 MHz. The method for forming a deposited film according to claim 9, wherein the shape for making the impedance discontinuous is a shape in which a propagation path of high-frequency power is partially branched. The method for forming a deposited film according to claim 9, wherein the shape for making the impedance discontinuous is a shape obtained by folding a part of a high-frequency power propagation path. The method for forming a deposited film according to claim 9, wherein the shape for making the impedance discontinuous is a coil shape. Said substrate is formed of a plurality of cylindrical substrates, claim, characterized in that it is arranged on the same circumference such that the cylindrical body of the plurality of surrounding the deposition space in the reaction vessel 9 The method for forming a deposited film according to claim 13 .

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