JP3606399B2 - Deposited film forming equipment - Google Patents

Description

【００２７】
【表２】

［実施例２］
実施例１において誘電体１１２の材料として、テフロン、石英ガラス、テフロンホウケイ酸ガラス、酸化アルミニウム、酸化マグネシウム、酸化珪素、酸化アルミニウムと酸化マグネシウムをモル比で１：１含むもの、酸化アルミニウムと酸化珪素をモル比で１：１含むもの、酸化マグネシウムと酸化珪素をモル比で１：１含むもの、酸化アルミニウムと酸化珪素と酸化マグネシウムをモル比で１：１：１含むものをそれぞれ用いて真空中で補助基体１０３と誘電体１１２、アース電極１０６で構成するコンデンサが１５．３ｐＦになるようにそれぞれ大きさと間隔を設定した以外は実施例１と同様な条件でアルミニューム製の円筒状基体１０２にａ−Ｓｉ膜を形成し、電子写真用感光体を作製した。
実施例２で作製した電子写真感光体を実施例１と同様の手順で膜厚ムラ、堆積速度、帯電ムラ、感度ムラ、ガサツキ、白ポチ、特性の再現性について評価した結果、実施例１と同様に良好な結果が得られた。
以上の結果より、誘電体を変化させても本発明の堆積膜形成装置を用いることにより良好な堆積膜が得られることが分かった。
【００２８】
［実施例３］
図５に示した堆積膜形成装置において発振周波数１０５ＭＨｚの高周波電源５１０を設置し、アルミニューム製の円筒状基体５０１にａ−Ｓｉ膜を形成し、電子写真用感光体を作製した。本堆積膜形成装置の回転軸を円柱と近似して計算によりインダクタンスＬを計算したところ０．１５μＨであった。そこでＣ＝（４π^２ｆ^２Ｌ）^−１に当てはめてＣを計算したところ本実施例では１５．３ｐＦとなった。よって、真空中で補助基体５０３と誘電体５１２、アース電極５０６で構成するコンデンサがこの値になるように誘電体５１２としてアルミナセラミックス、アース電極５０６としてアルミニュームを用いて大きさと間隔を設定した。本実施例では、アース電極５０６及び誘電体５１２は円筒状とし、補助基体５０３の周方向全周に渡って設置した。
成膜条件として、表１に示された製造条件に従って成膜を行った。
【００２９】
（比較例３）
図７に示した従来の堆積膜形成装置において発振周波数１０５ＭＨｚの高周波電源７１０を設置し、アルミニューム製の円筒状基体７０２にａ−Ｓｉ膜を形成し、電子写真用感光体を作製した。
成膜条件として、表１に示された製造条件に従って成膜を行った。
実施例３、比較例３で作製した電子写真感光体は実施例１と同様の手順で膜厚ムラ、堆積速度、帯電ムラ、感度ムラ、ガサツキ、白ポチ、特性の再現性について評価した。その結果を表３に示すが、本発明の堆積膜形成装置では画像欠陥は悪化せず膜厚、特性ムラ、特性の再現性が改善し、やはり堆積速度も向上している。
【００３０】
【表３】

［実施例４］
図２に示した堆積膜形成装置において発振周波数６０ＭＨｚの高周波電源２１０を設置し、アルミニューム製の円筒状基体２０２にａ−Ｓｉ膜を形成し、電子写真用感光体を作製した。本堆積膜形成装置の回転軸を円柱と近似して計算によりインダクタンスＬを計算したところ０．０７μＨであった。そこでＣ＝（４π^２ｆ^２Ｌ）^−１に当てはめてＣを計算したところ本実施例では１００ｐＦとなった。本実施例では本発明のコンデンサの値を０．１Ｃ、Ｃ、５Ｃ、１０Ｃ（Ｃ＝１００ｐＦ）に変化させて本発明の効果を調べた。本実施例では、真空中で補助基体５０３と誘電体５１２、アース電極５０６で構成するコンデンサが上記の値になるように誘電体１１２としてアルミナセラミックス、アース電極１０６としてアルミニュームを用いてそれぞれ大きさと間隔を設定した。本実施例では、アース電極５０６及び誘電体５１２は円筒状とし、補助基体５０３の周方向全周に渡って設置した。
【００３１】
成膜条件として、表１に示された製造条件に従って成膜を行った。
【００３２】
（比較例４）
実施例４において本発明のコンデンサの値を０．０５Ｃ、１５Ｃ（Ｃ＝１００ｐＦ）とした以外は実施例４と同様な条件でアルミニューム製の円筒状基体２０２にａ−Ｓｉ膜を形成し、電子写真用感光体を作製した。
実施例４、比較例４で作成した電子写真感光体は実施例１と同様の手順で膜厚ムラ、堆積速度、帯電ムラ、感度ムラ、ガサツキ、白ポチ、特性の再現性について評価した。その結果を表４に示す。本発明のコンデンサの値が０．１Ｃから１０Ｃでは本発明の効果が得られているが、０．０５Ｃ、１５Ｃまで値がずれると効果が薄れることが明確になった。
又、堆積速度についてもコンデンサの容量が０．１Ｃ以上で改善が見られる。
【００３３】
【表４】

［実施例５］
図４に示した堆積膜形成装置においてアルミニューム製の円筒状基体４０２にａ−Ｓｉ膜を形成し、電子写真用感光体を作製した。本堆積膜形成装置の回転軸を円柱と近似して計算によりインダクタンスＬを計算し本発明のコンデンサの値を求めて誘電体４１２としてアルミナセラミックス、アース電極４０６としてアルミニュームを用いてそれぞれ大きさと間隔を設定した。本実施例では、アース電極４０６及び誘電体４１２は円盤状とし、補助基体４０３の周方向全周に渡って設置した。本実施例では、高周波電源４１０の周波数を２０ＭＨｚ、５０ＭＨｚ、３００ＭＨｚ、４５０ＭＨｚとし、成膜条件として、表５に示された製造条件に従って成膜を行った。
【００３４】
（比較例５）
図４に示した堆積膜形成装置において実施例５と同様にアルミニューム製の円筒状基体４０２にａ−Ｓｉ膜を形成し、電子写真用感光体を作製した。但し、本比較例では高周波電源４１０の周波数を１３．５６ＭＨｚ、５００ＭＨｚとした。但し、周波数１３．５６ＭＨｚでは電荷輸送層、電荷発生層、表面保護層の内圧をそれぞれ２００ｍＴｏｒｒ、３００ｍＴｏｒｒ、３５０ｍＴｏｒｒにした。実施例５、比較例５で作製した電子写真感光体は実施例１と同様の手順で膜厚ムラ、堆積速度、帯電ムラ、感度ムラ、ガサツキ、白ポチ、特性の再現性について評価を行った。
その結果を表６に示す。高周波電源の周波数が２０ＭＨｚ〜４５０ＭＨｚでは本発明の効果が得られており、かつ成膜時間の短縮が図れるが、１３．５６ＭＨｚでは成膜時間の短縮は図れず、また５００ＭＨｚになると軸方向で更に別のムラが発生し、本発明の効果が得られなくなることが分かる。
【００３５】
［実施例６］
図５に示した複数の円筒状基体を同時に成膜出来る堆積膜形成装置において発振周波数１０５ＭＨｚの高周波電源５１０を設置し、アルミニューム製の円筒状基体５０２にａ−Ｓｉ膜を形成し、電子写真用感光体を作製した。本堆積膜形成装置の回転軸を円柱と近似して計算によりインダクタンスＬを計算したところ０．２μＨであった。そこで、Ｃ＝（４π^２ｆ^２Ｌ）^−１に当てはめてＣを計算したところ本実施例では１１．５ｐＦとなった。よって、真空中で補助基体５０３と誘電体５１２、アース電極５０６で構成するコンデンサが上記の値になるように誘電体１１２としてアルミナセラミックス、アース電極１０６としてアルミニュームを用いてそれぞれ大きさと間隔を設定した。本実施例では、アース電極５０６及び誘電体５１２は円筒状とし、補助基体５０３の周方向半周にのみ面するように設置した。成膜条件として、表５に示された製造条件に従って成膜を行った。実施例６で作製した感光体の評価を実施例１と同様に膜厚ムラ、堆積速度、帯電ムラ、感度ムラ、ガサツキ、白ポチ、特性の再現性について行ったところ、いずれの感光体も実施例１と同様の良好な結果が得られた。
更に得られた感光体をキヤノン製複写機ＮＰ−６６５０に設置し画像を出したところ、ハーフトーン画像にムラはなく、均一な画像が得られた。更に文字原稿を複写したところ、黒濃度が高く鮮明な画像が得られた。また写真原稿の複写においても原稿に忠実で鮮明な画像を得ることが出来た。
【００３６】
［実施例７］
図３に示した堆積膜形成装置において発振周波数６０ＭＨｚの高周波電源３１０を設置し、アルミニューム製の円筒状基体３０２にａ−Ｓｉ膜を形成し、電子写真用感光体を作製した。本実施例ではアース電極３０６としてアルミニューム、誘電体３１２としてアルミナセラミックスを用い円筒状基体の周方向１／６周のみと面する形状のものを設置した。アース電極３０６、誘電体３１２の大きさと間隔は本堆積膜形成装置の回転軸を円柱と近似して計算によりインダクタンスＬを計算し本発明のコンデンサの値を求めて設定した。
成膜条件として、表５に示された製造条件に従って成膜を行った。
実施例７で作製した感光体の評価を実施例１と同様に膜厚ムラ、堆積速度、帯電ムラ、感度ムラ、ガサツキ、白ポチ、特性の再現性について行ったところ、いずれの感光体も実施例１と同様の良好な結果が得られた。
更に得られた感光体をキヤノン製複写機ＮＰ−６６５０に設置し画像を出したところ、ハーフトーン画像にムラはなく、均一な画像が得られた。更に文字原稿を複写したところ、黒濃度が高く鮮明な画像が得られた。また写真原稿の複写においても原稿に忠実で鮮明な画像を得ることができた。
【００３７】
【表５】

【００３８】
【表６】

【００３９】
【発明の効果】
本発明は、以上のように反応容器に回転可能に配置された円筒状基体の母線方向のいずれか一方の端部を、前記基体の回転軸により接地させ、その他方の端部はこれと非接触のコンデンサを介し接地させることにより、高い周波数による成膜において、膜厚分布の発生を無くすことができる。
特に、２０ＭＨｚ〜４５０ＭＨｚの高周波電力による成膜において、画像欠陥を増加させることなく軸方向の膜厚ムラの低減を図ることができ、濃度ムラ、感度ムラ、画像のがさつきが無く、特性の再現性が良好で、高速の処理速度で比較的大面積の膜形成が可能な堆積膜の形成装置を実現することができ、とりわけ短時間のもとで低コストの電子写真用感光体の製造が可能となる。
【図面の簡単な説明】
【図１】１本の円筒状基体を成膜するのに供される本発明の堆積膜形成装置の一例を示す模式図である。
【図２】１本の円筒状基体を成膜するのに供される本発明の堆積膜形成装置の一例を示す模式図である。
【図３】１本の円筒状基体を成膜するのに供される本発明の堆積膜形成装置の一例を示す模式図である。
【図４】１本の円筒状基体を成膜するのに供される本発明の堆積膜形成装置の一例を示す模式図である。
【図５】複数本の円筒状基体を成膜するのに供される本発明の堆積膜形成装置の一例を示す模式図である。
【図６】本発明外の従来の堆積膜形成装置の一例を示す模式図である。
【図７】複数本の円筒状基体を成膜するのに供される本発明外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、２００、３００、４００、５００、６００、７００…堆積室
１０１、２０１、３０１、４０１、５０１、６０１、７０１…カソード電極
１０２、２０２、３０２、４０２、５０２、６０２、７０２…円筒状基体
１０３、２０３、４０３、５０３、６０３、７０３…補助基体
１０４、２０４、３０４、４０４、５０４、６０４、７０４
…基体加熱用ヒーター
１０５、２０５、３０５、４０５、５０５、６０５、７０５…回転軸
１０６、２０６、３０６、４０６、５０６…アース電極
１０７、２０７、３０７、４０７、５０７、６０７、７０７…原料ガス導入口
１０８、２０８、３０８、４０８、５０８、６０８、７０８
…基体駆動用モーター
１０９、２０９、３０９、４０９、５０９、６０９、７０９…整合器
１１０、２１０、３１０、４１０、５１０、６１０、７１０…高周波電源
１１１、２１１、３１１、４１１、５１１、６１１、７１１…排気口
１１２、２１２、３１２、４１２、５１２、・・・誘導体[0001]
[Industrial application fields]
The present invention is a plasma capable of satisfactorily forming crystalline and non-single crystalline functional deposition films useful for electrophotographic photoreceptor devices as semiconductor devices, image input line sensors, imaging devices, photovoltaic devices and the like. A CVD apparatus, a semiconductor device, a sputtering apparatus capable of suitably forming an insulating film as an optical element, a metal wiring, etc., or a deposited film forming apparatus by plasma processing such as an etching apparatus for a semiconductor device, and more particularly, The present invention relates to a plasma processing apparatus for processing a substrate using plasma as an excitation source, and more particularly to a plasma processing apparatus that can suitably use a high frequency of 20 MHz to 450 MHz.
[0002]
[Prior art]
There are various methods for plasma processing apparatuses used in semiconductors and the like depending on their applications.
For example, in the film formation, an oxide film or a nitride film formed using a plasma CVD apparatus or a plasma CVD method, an amorphous silicon semiconductor film, a metal wiring film using a sputtering apparatus or a sputtering method, an etching apparatus or a method is used. Devices and methods that make use of various features such as microfabrication technology are used.
Furthermore, in recent years, demands for improving film quality and processing capacity have increased, and various ideas have been studied.
In particular, a plasma process using high-frequency power has a high discharge stability and is used for various advantages such as being able to be used for forming a green material such as an oxide film or a nitride film.
Conventionally, 13.56 MHz is generally used as the oscillation frequency of a discharge high-frequency power source used in a plasma process such as plasma CVD. FIG. 6 shows an example of a plasma CVD apparatus generally used for the conventional deposition film formation. The plasma CVD apparatus shown in FIG. 6 is a film forming apparatus suitable for forming an amorphous silicon film (hereinafter referred to as “a-Si film”) on a cylindrical electrophotographic photosensitive member substrate.
[0003]
Hereinafter, a method for forming an a-Si film using this apparatus will be described.
A cathode substrate 601 and a cylindrical substrate 602 as a counter electrode are disposed in a deposition chamber 600 that can be depressurized. An auxiliary base 603 is attached to the cylindrical base 602 and forms a part of the electrode. The cylindrical substrate 602 is heated from the inside by an internal substrate heater 604. The high frequency power supply 610 is connected to the cathode electrode 601 at one location via the matching circuit 609. Reference numeral 611 denotes an exhaust port, and 607 denotes a raw material gas introduction port.
A cylindrical base is installed in the deposition chamber 600, and the deposition chamber 600 is once exhausted by an exhaust device (not shown) through the exhaust port 611. Thereafter, a raw material gas introduction port (not shown) is opened, an inert gas is introduced, and the flow rate and the exhaust speed are adjusted so that a predetermined pressure is obtained. The substrate heating heater 604 is energized while rotating the cylindrical substrate in the circumferential direction by the drive motor 608 to heat the cylindrical substrate to a desired temperature of 100 to 400 ° C.
Thereafter, a raw material gas for film formation, for example, a material gas such as silane gas, disilane gas, methane gas, and ethane gas, and a doping gas such as diborane gas and phosphine gas are mixed through a raw material gas inlet 607 with a mixing panel (not shown). Then, the exhaust speed is adjusted so that the pressure is maintained from several tens of mTorr to several Torr.
A high frequency power of 13.56 MHz is supplied from a high frequency power source 610 to one location of the cathode electrode 601 through the matching circuit 609, and plasma discharge is generated between the cylindrical base 602 and the source gas is decomposed, thereby generating a cylindrical shape. An a-Si film is deposited on the substrate 602. During this time, the cylindrical substrate is maintained at about 100 to 400 ° C. by the substrate heater 604, and the cylindrical substrate is also rotated in the circumferential direction.
[0004]
When an a-Si film is deposited on a cylindrical substrate for a copying machine according to the above procedure, the circumferential direction of the cylindrical substrate is also improved in order to improve circumferential uniformity in the coaxial film forming apparatus shown in FIG. It is desirable to form the film while rotating the film.
In addition, in a device as shown in FIG. 7 in which a plurality of cylindrical substrates are installed concentrically and an electrode is installed inside the cylindrical substrates to generate discharge, a film is deposited on the entire circumference of the substrate. Rotation is essential to make it happen. In the figure, reference numeral 700 denotes a deposition chamber, which has a vacuum-tight structure. And it is connected to an exhaust device (not shown) through an exhaust port 711. Reference numeral 701 denotes a cathode electrode which is connected to a high frequency power source 710 via a matching unit 709.
Reference numeral 707 denotes a raw material gas inlet, which is connected to a gas supply source (not shown). A cylindrical substrate 702 is installed in the deposition chamber 700. An auxiliary base 703 is attached to the cylindrical base 702 and forms a part of the electrode. The substrate heating heater 704 is installed on a rotating shaft 705 arranged concentrically. The rotating shaft 705 can be rotated by a substrate driving motor 708. Hereinafter, the film forming method is the same as in the case of using FIG.
At the same time, in general, in a plasma CVD apparatus, since it is necessary to maintain the substrate temperature during film formation at 100 to 400 ° C., a heater for heating the substrate is essential. The capacity of this heater is as large as 0.5 to 5 kW because it is necessary to heat the substrate in a vacuum where heat is not easily transmitted, and it is difficult and difficult to supply power in a rotating shaft that rotates the substrate. For this reason, the substrate heating heater is generally fixed in the deposition chamber in order to simplify the structure of the apparatus, reduce costs, and facilitate maintenance.
For this reason, the rotating shaft is installed so as to pass through the heater for heating the substrate, and the cylindrical substrate is heated and rotated by supporting the upper portion of the cylindrical substrate with this rotating shaft.
[0005]
The deposition rate for obtaining an a-Si film satisfying the performance of the electrophotographic photoreceptor by this film forming method is, for example, about 0.5 to 6 μm per hour, and the deposition rate is further increased. In some cases, characteristics as a photoconductor cannot be obtained. In general, when an a-Si film is used as an electrophotographic photoreceptor, a film thickness of at least 20 to 30 μm is necessary to obtain charging ability, and a long time is required to produce an electrophotographic photoreceptor. It was necessary. For this reason, a technique for shortening the manufacturing time without deteriorating the characteristics as a photoreceptor has been desired.
Recently, there has been a report of a plasma CVD method using a parallel plate type plasma CVD apparatus and a high frequency power source of 20 MHz or more (Plasma Chemistry and Plasma Processing, vol. 7, No. 3, (1987) p267-273), The possibility that the deposition rate can be improved without degrading the performance of the deposited film by increasing the discharge frequency from the conventional 13.56 MHz has been shown and is attracting attention. Moreover, the report which raises this discharge frequency is made | formed also by sputtering etc., and the superiority is examined widely in recent years.
Therefore, in order to improve the deposition rate, the discharge frequency was changed to high-frequency power with a frequency higher than the conventional 13.56 MHz, and the film formation procedure was performed by the same method as the conventional method. I was able to confirm that it was possible.
[0006]
[Problems to be solved by the invention]
However, it has been found that the following problems may be newly generated which did not become a problem at the discharge frequency of 13.56 MHz in the conventional example.
When the substrate heater is fixed in the deposition chamber and the rotation shaft passes through the inside of the deposition chamber, the cylindrical substrate is connected to the ground from one place by contacting the rotation shaft. When film formation is performed using power of a high frequency of 20 MHz to 450 MHz with this configuration, there is an adverse effect that a film thickness distribution that is not a problem at a low frequency of 13.56 MHz occurs. In other words, this is a phenomenon in which the film thickness on the grounding side becomes thicker and becomes thinner on the opposite side.
This also changes the film quality of the deposited film in the longitudinal direction, and the electrophotographic photosensitive member is liable to cause adverse effects such as density unevenness, sensitivity unevenness, and image roughness. Further, if the opposite side to the side grounded by the rotating shaft is forcibly grounded by rubbing, for example, an earth electrode, the dust is generated due to the rubbing of the metals, for example, an electron. In the case of a photographic photosensitive member, the image defect is very deteriorated and cannot be practically used.
Furthermore, there is a problem in the reproducibility of characteristics because the plasma state is different and unstable on the opposite side to the grounded side.
As described above, in film formation using high-frequency power with a high frequency of 20 MHz or more, it is difficult to ground the cylindrical substrate from above and below, and this causes uneven film thickness and uneven film quality in the axial direction of the substrate. However, for example, when used for an electrophotographic photoreceptor, image unevenness such as density unevenness, sensitivity unevenness, and roughness may occur, image defects may be deteriorated, and there is also a problem in reproducibility of characteristics. .
The above-mentioned problems can occur when forming a crystalline or non-single crystalline functional deposition film that is useful only for electrophotographic photoreceptors, line sensors for image input, imaging devices, photovoltaic devices, etc. It becomes a big problem. Also, in other plasma processes such as dry etching and sputtering, the same problem occurs when the discharge frequency is increased, and this is a serious problem in practice.
[0007]
Therefore, the present invention solves the above problem, and enables film thickness unevenness in the axial direction to be reduced without increasing image defects in film formation with high frequency, particularly high frequency power of 20 MHz to 450 MHz. Providing deposition film forming equipment that has low sensitivity and image roughness, good reproducibility of characteristics, and enables relatively large area film formation at a high processing speed with a short manufacturing time and low cost. It is intended to do.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the present invention grounds one end in the generatrix direction of a cylindrical substrate rotatably arranged in the reaction vessel by the rotation axis of the substrate, and the other end is By preventing the adverse effect of the above-mentioned film thickness distribution by grounding through a non-contact capacitor with the end portion configured by arranging a dielectric and a ground electrode in order from the cylindrical base or the auxiliary base. It is.
That is, the present invention includes a vacuum-tight reaction vessel having exhaust means and source gas supply means, and a cylindrical substrate or auxiliary substrate that also serves as one electrode that can be rotated by a rotating shaft in the discharge space of the reaction vessel. In a deposited film forming apparatus in which an attached cylindrical substrate is installed, high frequency power of 20 MHz to 450 MHz is applied between the one electrode and a separately provided cathode electrode, and a deposited film is formed on the cylindrical substrate. One end of the cylindrical base in the generatrix direction is grounded by contact with the rotating shaft, and the other end is provided with a dielectric and a ground electrode in order from the cylindrical base or the auxiliary base. It is characterized in that it is grounded through a non-contact capacitor with the constructed end portion.
With this configuration, the present invention can achieve good results even at a frequency higher than the conventional 13.56 MHz of 20 MHz to 450 MHz.
In the present invention, the capacitor may be disposed at the entire outer periphery, a part of the outer periphery, the entire inner periphery, or a part of the inner periphery of the cylindrical substrate or the auxiliary substrate.
And, when the cylindrical substrate is arranged vertically in the discharge space of the reaction vessel, the ground is held and grounded by the rotating shaft at the upper part of the cylindrical substrate in the generatrix and the lower part by the capacitor. It can be carried out by grounding, or by holding and grounding the lower part of the cylindrical base in the generatrix direction by the rotating shaft and grounding the upper part by the capacitor.
In the present invention, a plurality of the cylindrical substrates may be arranged concentrically in the discharge space of the reaction vessel, and in that case, a cathode electrode is provided in the space surrounded by the cylindrical substrates. To do.
In the present invention, the dielectric is at least one of alumina ceramics, Teflon, quartz glass, and borosilicate glass, or at least one element oxide of aluminum oxide, magnesium oxide, and silicon oxide. Can be comprised by what has as a main component.
In the present invention, the capacitance C (farad) of the capacitor is 0.1 (4π) when the frequency of the high frequency power is f (hertz) and the inductance of the rotating shaft is L (Henry).²f²L)^-1≦ C ≦ 10 (4π²f²L)^-1
It is preferable to satisfy.
Furthermore, 0.5 (4π²f²L)^-1≦ C ≦ 5 (4π²f²L)^-1
It is more preferable to satisfy the above condition.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, as described above, one end of the cylindrical substrate rotatably arranged in the reaction vessel is grounded by the rotation axis of the substrate, and the other end is connected to this. By grounding via a non-contact capacitor, the above-described adverse effects of the film thickness distribution are prevented.
This will be further explained. As already described, the conventional method of grounding a long substrate such as a cylindrical substrate for a copying machine from a single place is to form a film at a low frequency of 13.56 MHz. There was no problem in that case.
However, when film formation is performed using high frequency power of 20 MHz to 450 MHz, the influence of the impedance of the substrate itself cannot be ignored. For this reason, in the longitudinal direction of the substrate, there is an adverse effect that the plasma state is different between the grounded side and the ungrounded value and the film thickness distribution is generated.
In other words, on the side where the ground is taken, the impedance to the ground is low, so the plasma density increases, the deposition rate increases, and the film thickness increases. On the other side, a self-bias is generated due to the impedance of the cylindrical substrate itself. For this reason, the plasma density is reduced and the film thickness is also reduced. Further, the film quality of the deposited film in the longitudinal direction naturally changes because the plasma density and deposition rate change, and in electrophotographic photoreceptors, it causes density unevenness, image blurring, sensitivity unevenness, and characteristics. There is also a problem with the reproducibility.
[0010]
As the most fundamental solution to this problem, the present inventor prepared for the generation of dust and grounded the cylindrical substrate opposite to the side supported by the rotating shaft with a grounded brush electrode. An experiment was conducted in which the ground state of the cylindrical substrate was apparently symmetrical.
Surprisingly, however, in this experiment, the grounding side on the rotating shaft was thin and the grounding electrode side was thick. The reason for this is that the grounded side of the rotating shaft is certainly grounded, but when viewed from a high frequency, it is grounded via a long path called the rotating shaft, so the impedance of this path is the brush. It is considered that the film thickness distribution is generated because the plasma state is different because the impedance is far larger than the impedance on the side grounded via the electrode.
Therefore, the method of rubbing with a brush-like electrode grounded on the side opposite to the side supported by the rotating shaft is not effective in terms of not only generating dust but also reducing the film thickness distribution and improving the reproducibility of characteristics. It has been found.
Based on the above results, in order to eliminate the generation of dust, to eliminate the axial unevenness of the cylindrical substrate, and to improve the reproducibility of the characteristics, there is a certain degree of resistance in high frequency without contact with the cylindrical substrate. I came to the conclusion that it was necessary to drop to earth. Then, a capacitor was considered as a structure having such a function.
In this case, for example, in the case of a cylindrical substrate whose upper part is supported by a rotating shaft, an earth electrode grounded to the deposition chamber in the vicinity of the lower side of the cylindrical substrate does not hinder the rotation of the substrate. It is mentioned that it is installed. That is, in this way, the cylindrical base and the earth electrode grounded form a kind of capacitor. In a conventional plasma CVD apparatus using a low frequency, the capacitor formed in this way has a capacity that is too small to cause a current to flow. However, when a high frequency such as 20 to 450 MHz is used as in the present invention, this is the case. Even with a low-capacitance capacitor, a sufficient amount of current can flow and it can be grounded.
[0011]
As a result of further intensive studies, it was found that the plasma flowed between the ground electrode and the cylindrical substrate and the capacitance of the capacitor formed between the ground electrode and the cylindrical substrate changed, and the reproducibility of the characteristics was improved. As a means for stabilizing, it was considered to install a dielectric between the end of the cylindrical substrate opposite to the side grounded by the rotating shaft and the ground electrode. In this way, in a capacitor of the same capacity, the space between the end of the cylindrical substrate opposite to the side grounded by the rotating shaft and the ground electrode is smaller than in the case where there is no dielectric, so that plasma can flow in. Experiments were conducted on the assumption that the reproducibility of the characteristics was reduced and the characteristics were stable. As a result, it was found that a better deposited film can be obtained and the reproducibility of the characteristics can be improved as compared with the case where the conventional deposited film forming apparatus is used. And it turned out that a deposition rate improves rather than the case where it forms into a film using high frequency electric power of 20-450 MHz with the conventional deposited film formation apparatus. The reason for this is not clear, but it is thought that the impedance of the whole cylindrical substrate is lowered by taking the ground from the upper and lower two places, and the high frequency power can be applied more efficiently.
As described above, one end of the cylindrical base in the generatrix direction is grounded by the rotating shaft that rotates the cylindrical base, and the other end is installed in order from the cylindrical base in a state of being adjacent to each other without contacting the cylindrical base. The effect of the present invention can be obtained for the first time by forming a capacitor between the dielectric and the earth electrode and grounding it without contact.
[0012]
In order to form the C coupling directly with the cylindrical substrate, a dielectric and a ground electrode may be provided in order from the cylindrical substrate in an adjacent state without contacting the outside or the inside of the cylindrical substrate.
In addition, when film formation is performed by attaching auxiliary substrates above and below the cylindrical substrate, a dielectric and a ground electrode are provided in order from the cylindrical substrate in an adjacent state without contacting the outside or the inside of the auxiliary substrate. It ’s fine. The dielectric and the ground electrode installed in this order from the cylindrical substrate may be provided over the entire circumference of the cylindrical substrate or the auxiliary substrate, or may be provided only in a part of the circumferential direction.
[0013]
In a deposited film forming apparatus that forms a film with high frequency power of a certain frequency f (Hz), if the inductance of the rotating shaft is L (H), the C coupling capacitance C (F) of the present invention can be obtained by the following equation.
C = (4π²f²L)^-1
The inductance of the rotating shaft is difficult to calculate when the shape is complicated, but if you use a value approximated as a roughly cylindrical bar, the effect of the present invention can be obtained sufficiently, so you need to pay less attention Absent. Of course, it may be obtained from actual measurement using an LCR meter or the like. Further, it is not necessary to strictly realize the value of C obtained from the calculation, and if the design is made so that it falls between 0.1 times and 10 times, the effect of the present invention can be improved to a level where there is no practical problem. . To specifically design the C coupling from the value of C obtained from the above equation,
C = ε1ε2S / {ε1d2 + ε2 (d1 + d3)}
What is necessary is just to attach the dielectric material and earth electrode which were installed so that it might satisfy | fill. Where ε1 is the dielectric constant between the cylindrical substrate and the dielectric and between the dielectric and the ground electrode, ε2 is the dielectric constant of the dielectric, d1 is the distance between the cylindrical substrate and the dielectric, d2 is the width of the dielectric, d3 is the distance between the dielectric and the ground electrode, and S is the overlapping area of the dielectric, the ground electrode and the cylindrical substrate. Strictly speaking, the value of ε1 varies depending on the type and pressure of the raw material gas introduced into the deposition chamber, but the effect of the present invention can be sufficiently obtained even if the dielectric constant in vacuum is roughly used.
In the deposited film forming apparatus of the present invention, the cylindrical substrate can be rotated. However, the effect of the present invention cannot be obtained unless the cylindrical substrate is rotated. The effect of the present invention can be obtained even if film formation is performed. Further, if the cylindrical substrate holding mechanism is a mechanism for holding the upper or lower portion of the cylindrical substrate similar to the present case, the effect of the present case can be obtained even if it is not rotatable.
[0014]
Hereinafter, the present invention will be described in detail with reference to the drawings.
FIG. 1 schematically shows an example of an apparatus for carrying out the method of the present invention, which is suitable for producing a deposited film on a cylindrical substrate such as an electrophotographic photoreceptor. In FIG. 1, reference numeral 100 denotes a deposition chamber for forming a deposited film, which is connected to an exhaust device (not shown) through an exhaust port 111. Reference numeral 107 denotes a raw material gas inlet for introducing the raw material gas into the deposition chamber. The raw material gas is introduced into the deposition chamber from a gas supply system (not shown). Reference numeral 102 denotes a cylindrical base, which is set on the auxiliary base 103 and attached to the rotary shaft 105. The rotating shaft 105 is rotatably attached to the deposition chamber. The upper portion of the cylindrical base body 102 and the auxiliary base body 103 is connected to the ground by a rotating shaft 105. Reference numeral 104 denotes a substrate heating heater for heating the cylindrical substrate to a predetermined temperature, and is fixed in the deposition chamber. Further, the cylindrical base 102 is rotated by a drive motor 108 via a rotating shaft 105 to achieve a uniform film thickness in the circumferential direction. Reference numeral 110 denotes a high frequency power source that generates a high frequency of 20 MHz to 450 MHz, and the high frequency output is wired so as to be applied to the cathode electrode 101 via a matching circuit 109. Of course, the cathode electrode 101 may also serve as the inner wall of the deposition chamber 100 as shown in the figure.
[0015]
106 and 112 are a ground electrode and a dielectric according to the present invention, respectively, and the ground electrode 106, the dielectric 112, and the auxiliary base 103 are arranged in this order so as not to contact the auxiliary base 103, and overlap each other. The capacitor is formed in the area where The capacitance of the capacitor can be arbitrarily set by changing the height of the ground electrode 106 and the dielectric 112 and the distance between the dielectric 112, the ground electrode 106 and the auxiliary base 103. In this apparatus configuration, the upper portion of the cylindrical substrate 102 is installed in the deposition chamber via the rotation shaft 105. However, since the inductance of the rotation shaft cannot be ignored at a high frequency such as 20 MHz to 450 MHz, a certain amount of resistance is required before falling to the ground. have. The capacitance of the capacitor formed between the ground electrode 106 and the auxiliary base 103 is adjusted so as to have the same resistance as that due to the inductance. In particular,
C = (4π²f²L)^-1
The configuration may be set so that the value of C calculated by
[0016]
FIG. 2 schematically shows another example of an apparatus for carrying out the method of the present invention, which is suitable for producing a deposited film on a cylindrical substrate such as an electrophotographic photoreceptor. In this apparatus, the cylindrical substrate 202 and the auxiliary substrate 203 are supported so as to be suspended from the upper part of the deposition chamber. In this apparatus, the ground electrode 206 and the dielectric 212 are installed inside the auxiliary substrate. Other components are the same as those in FIG.
FIG. 3 schematically shows yet another example of an apparatus for carrying out the method of the present invention. In this apparatus, the substrate heater 304 is attached to the upper portion of the deposition chamber, and the cylindrical substrate 302 is installed on the rotating shaft 305 attached to the lower portion of the deposition chamber. In this example, the auxiliary substrate is not used, and if the ground electrode 306 is provided outside the cylindrical substrate 302, the film thickness distribution is uneven, and therefore, the auxiliary substrate is installed inside the cylindrical substrate 302. Other components are the same as those in FIG.
FIG. 4 schematically shows another example of the shapes of the dielectric 412, the ground electrode 406, and the auxiliary base 403 according to the present invention. Of course, a capacitor may be formed by providing
[0017]
FIG. 5 schematically shows still another example of the present invention. The capacitor portion for grounding the lower portion of the cylindrical substrate 502 is the same as that shown in FIG. 1, but in this example, six cylindrical substrates are arranged concentrically, a cathode electrode 501 is installed at the center, and the cylindrical substrate is arranged. Discharge occurs in a space surrounded by 502.
[0018]
Any material can be used for the ground electrodes 106, 206, 306, 406, and 506 as long as it is resistant to heat and has high conductivity. In addition, it is preferable that the material used for the purpose of minimizing the inductance of the ground electrodes 106, 206, 306, 406, and 506 itself has a low magnetic permeability. Further, since the high frequency wave is conducted only on the outermost surface of the conductor by the skin effect, a shape having a surface area as large as possible is preferable.
In general, a flat plate shape is used. As specific materials for the ground electrodes 106, 206, 306, 406, and 506, copper, aluminum, gold, silver, and platinum are preferable because they have high conductivity and low magnetic permeability. Lead, nickel, cobalt, iron, chromium, molybdenum, titanium, and stainless steel are also suitable because they are resistant to heat. Or the composite material of 2 or more types in these materials is also preferable.
Materials used for the dielectrics 112, 212, 312, 412, and 512 include one or more elements of alumina ceramics, Teflon, quartz glass, borosilicate glass, or element oxides of aluminum oxide, magnesium oxide, and silicon oxide. There is no particular limitation as long as it is an insulating material resistant to heat, such as an oxide-based component.
As the high frequency power supply 110, 210, 310, 410, 510 used, any oscillation frequency of 20 MHz to 450 MHz can be used. Further, any output having an output of 10 W to 5000 W or more can be suitably used as long as it can generate electric power suitable for the apparatus. Furthermore, the effect of the present invention can be obtained regardless of the value of the output fluctuation rate of the high-frequency power source.
[0019]
The matching devices 1009, 209, 309, 409, and 509 used can be suitably used in any configuration as long as the matching between the high-frequency power source and the load can be achieved.
In addition, as a method for obtaining the alignment, an automatically adjusted method is preferable in order to avoid the complexity at the time of manufacture, but even the manually adjusted method has no influence on the effect of the present invention. And it is desirable in terms of low cost. In addition, as for the position where the matching unit is placed, there is no problem if it is installed anywhere within the range where matching can be achieved, but it is better to place it so that the inductance of the wiring between the matching unit and the cathode is as small as possible. This is desirable because it makes it possible to match the conditions.
As the material of the cathode electrodes 101, 201, 301, 401, 501, copper, aluminum, gold, silver, platinum, lead, nickel, cobalt, iron, chromium, molybdenum, titanium, stainless steel, etc. have good heat conduction and electric conduction. Is also preferable.
Two or more kinds of composite materials among these materials are also preferably used. In addition, a cylindrical shape is preferable for ease of processing, but an elliptical shape or a polygonal shape may be used as necessary. The cathode electrodes 101, 201, 301, 401, and 501 may be provided with cooling means as necessary. As specific cooling means, cooling by water, air, liquid nitrogen, Peltier element or the like is used as necessary.
The cylindrical bases 102, 202, 302, 402, and 502 and the auxiliary bases 103, 203, 303, 403, and 503 of the present invention may be any material that has a material suitable for the intended use. As the material, copper, aluminum, gold, silver, platinum, lead, nickel, cobalt, iron, chromium, molybdenum, titanium, and stainless steel are preferable because of good electrical conduction. Further, two or more composite materials among these materials are also desirable for improving heat resistance. Furthermore, an insulating material such as polyester, polyethylene, polycarbonate, cellulose acetate, polypropylene, polyvinyl chloride, polyvinylidene chloride, polystyrene, glass, ceramics, or paper coated with a conductive material is desirable because the cost can be reduced.
[0020]
In the apparatus shown in FIG. 1, an example of the deposited film forming method of the present invention is performed as follows.
This procedure can be similarly applied to the apparatus shown in FIGS.
First, for example, the cylindrical substrate 102 whose surface is mirror-finished using a lathe is attached to the auxiliary substrate 103 and attached to the rotating shaft 105 so as to include the substrate heating heater 104 in the deposition chamber 100.
Next, the source gas introduction valve (not shown) is closed, the deposition chamber is once exhausted by an exhaust device (not shown) through the exhaust port 111, and then the source gas introduction valve (not shown) is opened to heat the inert gas for heating. As an example, argon is introduced into the deposition chamber from the source gas inlet 107, and the exhaust speed of the exhaust device and the flow rate of the heating gas are adjusted so that the deposition chamber has a desired pressure.
Thereafter, a temperature controller (not shown) is operated while rotating the cylindrical substrate 102 by the driving motor 108 to heat the cylindrical substrate 102 by the substrate heating heater 104.
When the cylindrical substrate 102 is heated to a desired temperature, a raw material gas introduction valve (not shown) is closed to stop the gas flow into the deposition chamber.
The deposited film is formed by opening a source gas introduction valve (not shown) and supplying a predetermined source gas, for example, a source gas such as silane gas, disilane gas, methane gas, and ethane gas, and a doping gas such as diborane gas and phosphine gas from the source gas inlet 107. After mixing by a mixing panel (not shown), the mixture is introduced into the deposition chamber 100, and the exhaust speed is adjusted so as to maintain the pressure from several mTorr to several Torr. After the pressure is stabilized, the high-frequency power supply 110 is turned on to supply power with a frequency of 20 MHz to 450 MHz to cause glow discharge. At this time, the matching circuit 109 is adjusted so that the reflected wave is minimized. The value obtained by subtracting the reflected power from the high-frequency incident power is adjusted to a desired value. When a desired film thickness is formed, the glow discharge is stopped, the flow of the source gas into the deposition chamber 100 is stopped, and the deposition chamber is once subjected to high vacuum. After the layer is pulled up, the formation of the layer is finished. During this time, it is desirable to perform film formation while rotating the cylindrical substrate in order to equalize the film thickness in the circumferential direction. When stacking deposited films having various functions, the above operation is repeated.
[0021]
Specific examples for demonstrating the effects of the present invention will be described below, but the present invention is not limited to the specific examples.
[0022]
【Example】
Hereinafter, although implementation of the present invention is explained, the present invention is not limited at all by these.
[Example 1]
In the deposited film forming apparatus shown in FIG. 1, a high frequency power source 110 having an oscillation frequency of 105 MHz was installed, an a-Si film was formed on a cylindrical substrate 102 made of aluminum, and an electrophotographic photoreceptor was produced. The inductance L was calculated by approximating the rotation axis of the deposited film forming apparatus to a cylinder and found to be 0.15 μH. So C = (4π²f²L)^-1When C was calculated by applying to the above, it was 15.3 pF in this example. Therefore, the size and the interval are set using alumina ceramics as the dielectric 112 and aluminum as the ground electrode 106 so that the capacitor composed of the auxiliary base 103, the dielectric 112, and the ground electrode 106 has this value in vacuum. In this embodiment, the ground electrode 106 and the dielectric 112 are cylindrical and installed over the entire circumference of the auxiliary base 103.
Film formation was performed according to the manufacturing conditions shown in Table 1.
[0023]
(Comparative Example 1)
In the conventional deposited film forming apparatus shown in FIG. 6, a high frequency power source 610 having an oscillation frequency of 105 MHz was installed, an a-Si film was formed on a cylindrical substrate 602 made of aluminum, and an electrophotographic photoreceptor was produced.
As film formation conditions, film formation was performed according to the manufacturing conditions shown in Table 1 in the same manner as in Example 1.
[0024]
(Comparative Example 2)
In the conventional deposited film forming apparatus shown in FIG. 6, the lower portion of the auxiliary substrate 603 was forcibly grounded by rubbing with a metal brush that had been grounded. In this comparative example, a high frequency power source 610 having an oscillation frequency of 105 MHz was installed, an a-Si film was formed on a cylindrical substrate 602 made of aluminum, and an electrophotographic photoreceptor was prepared.
As film formation conditions, film formation was performed in accordance with the manufacturing conditions shown in Table 1 as in Example 1.
[0025]
The electrophotographic photoreceptors prepared in Example 1 and Comparative Examples 1 and 2 were evaluated by the following methods.
(1) Evaluation of film thickness distribution and deposition rate
For each photoconductor, the film thickness at 16 positions in the axial direction was measured by an eddy current film thickness meter (manufactured by Kett Science Laboratory), and the difference between the maximum film thickness and the minimum film thickness was divided by the average film thickness. The ratio of film thickness distribution was defined and divided into the following ranks.
◎ Very good
○ Good
△ No problem in practical use
× Practical problems
At the same time, the deposition rate was determined by dividing the total film thickness by the deposition time and evaluated. The evaluation criteria for the deposition rate were based on the apparatus of Comparative Example 1 and ranked as follows.
◎ 20% faster than Comparative Example 1
○ 10-20% faster than Comparative Example 1
△ Same as Comparative Example 1
× Slower than Comparative Example 1
(2) Electrophotographic characteristics
Each photoconductor was set in an electrophotographic apparatus (an Canon NP6060 modified for experiment), and the electrophotographic characteristics such as initial charging ability and residual potential were evaluated as follows.
Charging unevenness: An electrophotographic photosensitive member is set in an experimental apparatus, a high voltage of +6 kV is applied to the charger to perform corona charging, and the surface potential of the dark part of the electrophotographic photosensitive member is measured at the development position with a surface potential meter. Five points are measured in the axial direction of the electrophotographic photosensitive member, and potential unevenness at this time is evaluated.
Uneven sensitivity …… Charge the electrophotographic photoreceptor to a constant dark surface potential. Immediately using a filter, a halogen lamp light excluding light having a wavelength region of 550 nm or less is irradiated, and the light amount is adjusted so that the bright portion surface potential of the electrophotographic photosensitive member becomes a predetermined value. The amount of light required at this time is converted from the lighting voltage of the halogen lamp light source. In this procedure, the five-point sensitivity is measured in the axial direction of the electrophotographic photosensitive member, and the sensitivity unevenness at this time is evaluated.
For each
◎ Very good
○ Good
△ No problem in practical use
× Practical problems
Image roughness: A halftone chart was copied, and the obtained halftone image was observed in detail, compared with a limit sample, and evaluated.
◎ There is no rust and it is very good
○ Slight rustling is seen but good
△ Slightly rough, but at a conventional level
× There are many rustlings and there are practical problems
White spot: A white spot with a diameter of 0.2 mm or more within the same area of a copy image obtained by copying a full black chart (part number: FY9-9073) made by Canon on a document table was evaluated. The evaluation categories are as follows.
◎ Very good
○ Good
△ There are white spots, but there is no practical problem at the conventional level.
× Many white spots and practical problems
Was used to evaluate.
(3) Reproducibility of characteristics
The measurement of uneven charging of electrophotographic characteristics of (2) was performed 10 times, and the reproducibility at that time was compared with the electrophotographic photosensitive member produced in Comparative Example 1,
◎ much better than Comparative Example 1
○ Better than Comparative Example 1
△ Equivalent to Comparative Example 1
× worse than Comparative Example 1
Evaluation was carried out using.
The above results are summarized in Table 2. The electrophotographic photosensitive member using the deposited film forming apparatus of the present invention has no unevenness and excellent reproducibility of the characteristics and is very excellent. However, the conventional deposited film forming apparatus does not improve the unevenness. Further, forcibly grounding with a metal brush with the lower part of the auxiliary substrate grounded will not improve unevenness but also deteriorate the white spot level, making it unusable for practical use. In addition, compared with the comparative example 1, in Example 1, the improvement of the deposition rate is seen. The reason for this is not clear, but it is thought that the impedance of the whole cylindrical substrate is lowered by taking the ground from the upper and lower two places, and the high frequency power can be applied more efficiently.
From the above examples, it has been found that the deposited film forming apparatus of the present invention can improve the reproducibility of unevenness and characteristics without deteriorating image defects, and can improve the deposition rate.
[0026]
[Table 1]

[0027]
[Table 2]

[Example 2]
In Example 1, as a material of the dielectric 112, Teflon, quartz glass, Teflon borosilicate glass, aluminum oxide, magnesium oxide, silicon oxide, a material containing aluminum oxide and magnesium oxide at a molar ratio of 1: 1, aluminum oxide and silicon oxide In a vacuum using those containing 1: 1 by mole, magnesium oxide and silicon oxide containing 1: 1, and those containing aluminum oxide, silicon oxide and magnesium oxide 1: 1: 1 by mole. The cylindrical substrate 102 made of aluminum is formed under the same conditions as in Example 1 except that the size and the interval are set so that the capacitor constituted by the auxiliary substrate 103, the dielectric 112, and the ground electrode 106 is 15.3 pF. An a-Si film was formed to produce an electrophotographic photoreceptor.
The electrophotographic photosensitive member produced in Example 2 was evaluated for film thickness unevenness, deposition rate, charging unevenness, sensitivity unevenness, roughness, white spots, and reproducibility of characteristics in the same procedure as in Example 1. Good results were obtained as well.
From the above results, it was found that a good deposited film can be obtained by using the deposited film forming apparatus of the present invention even when the dielectric is changed.
[0028]
[Example 3]
In the deposited film forming apparatus shown in FIG. 5, a high frequency power supply 510 with an oscillation frequency of 105 MHz was installed, an a-Si film was formed on a cylindrical substrate 501 made of aluminum, and an electrophotographic photoreceptor was produced. The inductance L was calculated by approximating the rotation axis of the deposited film forming apparatus to a cylinder and found to be 0.15 μH. So C = (4π²f²L)^-1When C was calculated by applying the above, it was 15.3 pF in this example. Therefore, the size and interval are set using alumina ceramics as the dielectric 512 and aluminum as the ground electrode 506 so that the capacitor composed of the auxiliary base 503, the dielectric 512, and the ground electrode 506 has this value in vacuum. In this embodiment, the ground electrode 506 and the dielectric 512 are cylindrical and installed over the entire circumference of the auxiliary base 503 in the circumferential direction.
Film formation was performed according to the manufacturing conditions shown in Table 1.
[0029]
(Comparative Example 3)
In the conventional deposited film forming apparatus shown in FIG. 7, a high frequency power source 710 having an oscillation frequency of 105 MHz was installed, an a-Si film was formed on a cylindrical substrate 702 made of aluminum, and an electrophotographic photoreceptor was produced.
Film formation was performed according to the manufacturing conditions shown in Table 1.
The electrophotographic photoreceptors prepared in Example 3 and Comparative Example 3 were evaluated for film thickness unevenness, deposition rate, charging unevenness, sensitivity unevenness, roughness, white spots, and property reproducibility in the same procedure as in Example 1. The results are shown in Table 3. In the deposited film forming apparatus of the present invention, the image defects are not deteriorated, the film thickness, the characteristic unevenness, the reproducibility of the characteristics are improved, and the deposition rate is also improved.
[0030]
[Table 3]

[Example 4]
In the deposited film forming apparatus shown in FIG. 2, a high frequency power supply 210 with an oscillation frequency of 60 MHz was installed, an a-Si film was formed on a cylindrical substrate 202 made of aluminum, and an electrophotographic photoreceptor was produced. The inductance L was calculated by approximating the rotation axis of the deposited film forming apparatus to a cylinder and found to be 0.07 μH. So C = (4π²f²L)^-1C was calculated by applying the above to 100 pF in this example. In this example, the effect of the present invention was examined by changing the value of the capacitor of the present invention to 0.1 C, C, 5 C, and 10 C (C = 100 pF). In the present embodiment, alumina ceramic is used as the dielectric 112 and aluminum is used as the ground electrode 106 so that the capacitor constituted by the auxiliary base 503, the dielectric 512, and the ground electrode 506 in the vacuum has the above values. An interval was set. In this embodiment, the ground electrode 506 and the dielectric 512 are cylindrical and installed over the entire circumference of the auxiliary base 503 in the circumferential direction.
[0031]
Film formation was performed according to the manufacturing conditions shown in Table 1.
[0032]
(Comparative Example 4)
In Example 4, an a-Si film was formed on an aluminum cylindrical substrate 202 under the same conditions as in Example 4 except that the value of the capacitor of the present invention was set to 0.05C and 15C (C = 100 pF). An electrophotographic photoreceptor was prepared.
The electrophotographic photoreceptors prepared in Example 4 and Comparative Example 4 were evaluated for film thickness unevenness, deposition rate, charging unevenness, sensitivity unevenness, roughness, white spots, and property reproducibility in the same procedure as in Example 1. The results are shown in Table 4. The effect of the present invention is obtained when the value of the capacitor of the present invention is 0.1 C to 10 C. However, it became clear that the effect diminishes when the value is deviated to 0.05 C and 15 C.
Also, the deposition rate is improved when the capacitance of the capacitor is 0.1 C or more.
[0033]
[Table 4]

[Example 5]
In the deposited film forming apparatus shown in FIG. 4, an a-Si film was formed on a cylindrical substrate 402 made of aluminum to produce an electrophotographic photoreceptor. By approximating the rotation axis of the deposited film forming apparatus to a cylinder, the inductance L is calculated by calculation, and the value of the capacitor of the present invention is obtained. It was set. In this embodiment, the ground electrode 406 and the dielectric 412 are disk-shaped and installed over the entire circumference of the auxiliary base 403 in the circumferential direction. In this example, the frequency of the high frequency power supply 410 was set to 20 MHz, 50 MHz, 300 MHz, and 450 MHz, and film formation was performed according to the manufacturing conditions shown in Table 5 as film formation conditions.
[0034]
(Comparative Example 5)
In the deposited film forming apparatus shown in FIG. 4, an a-Si film was formed on a cylindrical substrate 402 made of aluminum in the same manner as in Example 5 to produce an electrophotographic photoreceptor. However, in this comparative example, the frequency of the high frequency power supply 410 was set to 13.56 MHz and 500 MHz. However, at a frequency of 13.56 MHz, the internal pressures of the charge transport layer, the charge generation layer, and the surface protective layer were 200 mTorr, 300 mTorr, and 350 mTorr, respectively. The electrophotographic photoreceptors prepared in Example 5 and Comparative Example 5 were evaluated for film thickness unevenness, deposition rate, charging unevenness, sensitivity unevenness, roughness, white spots, and property reproducibility in the same procedure as in Example 1. .
The results are shown in Table 6. The effect of the present invention can be obtained when the frequency of the high frequency power source is 20 MHz to 450 MHz, and the film formation time can be shortened. It can be seen that another unevenness occurs and the effect of the present invention cannot be obtained.
[0035]
[Example 6]
In the deposited film forming apparatus capable of forming a plurality of cylindrical substrates shown in FIG. 5 at the same time, a high-frequency power source 510 with an oscillation frequency of 105 MHz is installed, an a-Si film is formed on the cylindrical substrate 502 made of aluminum, and electrophotography A photoconductor was prepared. The inductance L was calculated by approximating the rotation axis of the deposited film forming apparatus to a cylinder and found to be 0.2 μH. Therefore, C = (4π²f²L)^-1C was calculated by applying the above to 11.5 pF in this example. Therefore, the size and interval are set using alumina ceramics as the dielectric 112 and aluminum as the ground electrode 106 so that the capacitor composed of the auxiliary substrate 503, the dielectric 512, and the ground electrode 506 in the vacuum has the above values. did. In this embodiment, the ground electrode 506 and the dielectric 512 are cylindrical and installed so as to face only the half circumference of the auxiliary base 503 in the circumferential direction. Film formation was performed in accordance with the manufacturing conditions shown in Table 5. Evaluation of the photoconductor produced in Example 6 was performed in the same manner as in Example 1 in terms of film thickness unevenness, deposition rate, charging unevenness, sensitivity unevenness, roughness, white spots, and characteristic reproducibility. Good results similar to Example 1 were obtained.
Further, when the obtained photoreceptor was installed in a Canon copier NP-6650 and an image was taken out, there was no unevenness in the halftone image, and a uniform image was obtained. Further, when a character document was copied, a clear image with high black density was obtained. In copying a photographic manuscript, it was possible to obtain a clear image faithful to the manuscript.
[0036]
[Example 7]
In the deposited film forming apparatus shown in FIG. 3, a high frequency power source 310 with an oscillation frequency of 60 MHz was installed, an a-Si film was formed on a cylindrical substrate 302 made of aluminum, and an electrophotographic photoreceptor was produced. In this embodiment, the ground electrode 306 is made of aluminum, the dielectric 312 is made of alumina ceramics, and the one having a shape facing only 1/6 of the circumferential direction of the cylindrical substrate is installed. The sizes and intervals of the ground electrode 306 and the dielectric 312 were set by approximating the rotation axis of the deposited film forming apparatus to a cylinder and calculating the inductance L by calculation to obtain the value of the capacitor of the present invention.
Film formation was performed in accordance with the manufacturing conditions shown in Table 5.
Evaluation of the photoconductor produced in Example 7 was performed in the same manner as in Example 1 for film thickness unevenness, deposition rate, charging unevenness, sensitivity unevenness, roughness, white spots, and characteristic reproducibility. Good results similar to Example 1 were obtained.
Further, when the obtained photoreceptor was installed in a Canon copier NP-6650 and an image was taken out, there was no unevenness in the halftone image, and a uniform image was obtained. Further, when a character document was copied, a clear image with high black density was obtained. In copying a photographic manuscript, it was possible to obtain a clear image faithful to the manuscript.
[0037]
[Table 5]

[0038]
[Table 6]

[0039]
【The invention's effect】
In the present invention, as described above, one end of the cylindrical substrate disposed rotatably in the reaction vessel is grounded by the rotation axis of the substrate, and the other end is not in contact with this. By grounding through a contact capacitor, it is possible to eliminate the occurrence of film thickness distribution in film formation at a high frequency.
In particular, in film formation with high frequency power of 20 MHz to 450 MHz, it is possible to reduce the film thickness unevenness in the axial direction without increasing image defects, and there is no density unevenness, sensitivity unevenness, or image roughness, and the reproduction of characteristics. It is possible to realize a deposited film forming apparatus that can form a film with a relatively large area at a high processing speed, and can produce a low-cost electrophotographic photoreceptor in a short time. It becomes possible.
[Brief description of the drawings]
FIG. 1 is a schematic view showing an example of a deposited film forming apparatus of the present invention used for forming a single cylindrical substrate.
FIG. 2 is a schematic diagram showing an example of a deposited film forming apparatus of the present invention that is used to form a single cylindrical substrate.
FIG. 3 is a schematic diagram showing an example of a deposited film forming apparatus of the present invention used for forming a single cylindrical substrate.
FIG. 4 is a schematic view showing an example of a deposited film forming apparatus of the present invention used for forming a single cylindrical substrate.
FIG. 5 is a schematic view showing an example of a deposited film forming apparatus of the present invention provided for forming a plurality of cylindrical substrates.
FIG. 6 is a schematic view showing an example of a conventional deposited film forming apparatus outside the present invention.
FIG. 7 is a schematic view showing an example of a deposited film forming apparatus outside the present invention used for forming a plurality of cylindrical substrates.
[Explanation of symbols]
100, 200, 300, 400, 500, 600, 700 ... deposition chamber
101, 201, 301, 401, 501, 601, 701 ... cathode electrode
102, 202, 302, 402, 502, 602, 702 ... cylindrical base
103, 203, 403, 503, 603, 703 ... auxiliary substrate
104, 204, 304, 404, 504, 604, 704
... Heater for substrate heating
105, 205, 305, 405, 505, 605, 705 ... rotation axis
106, 206, 306, 406, 506 ... Earth electrode
107, 207, 307, 407, 507, 607, 707 ... Raw material gas inlet
108, 208, 308, 408, 508, 608, 708
... Substrate drive motor
109,209,309,409,509,609,709 ... matching device
110, 210, 310, 410, 510, 610, 710 ... high frequency power supply
111, 211, 311, 411, 511, 611, 711 ... exhaust port
112, 212, 312, 412, 512, ... derivatives

Claims (10)

A cylindrical substrate provided with a vacuum-tight reaction vessel having an evacuation unit and a raw material gas supply unit, and a cylindrical substrate or an auxiliary substrate that also serves as one electrode that can be rotated by a rotating shaft in the discharge space of the reaction vessel In the deposited film forming apparatus for forming a deposited film on the cylindrical substrate by applying a high frequency power of 20 MHz to 450 MHz between the one electrode and a separately provided cathode electrode, the cylindrical substrate One end of the bus in the direction of the bus is grounded by contact with the rotating shaft, and the other end is configured by arranging a dielectric and a ground electrode in order from the cylindrical base or the auxiliary base. A deposited film forming apparatus characterized by being grounded via a non-contact capacitor. 2. The deposited film forming apparatus according to claim 1, wherein the capacitor is provided on the entire outer periphery or a part of the outer periphery of the cylindrical substrate or the auxiliary substrate. 2. The deposited film forming apparatus according to claim 1, wherein the capacitor is provided on the entire inner periphery or a part of the inner periphery of the cylindrical substrate or the auxiliary substrate. The cylindrical substrate is vertically arranged in the discharge space of the reaction vessel, and the upper part of the cylindrical substrate in the generatrix direction is held and grounded by the rotating shaft, and the lower part is grounded by the capacitor. The deposited film formation apparatus of any one of Claims 1-3. The cylindrical substrate is arranged vertically in the discharge space of the reaction vessel, the lower part of the cylindrical substrate in the bus-bar direction is held and grounded by the rotating shaft, and the upper part is grounded by the capacitor. The deposited film formation apparatus of any one of Claims 1-4. The cylindrical substrate is characterized in that a plurality of cylindrical substrates are arranged concentrically in the discharge space of the reaction vessel, and a cathode electrode is installed in the space surrounded by the cylindrical substrate. The deposited film forming apparatus according to any one of claims 1 to 5. The deposited film forming apparatus according to claim 1, wherein the dielectric is made of at least one of alumina ceramics, Teflon, quartz glass, and borosilicate glass. 2. The deposited film forming apparatus according to claim 1, wherein the dielectric is composed mainly of at least one element oxide of element oxides of aluminum oxide, magnesium oxide, and silicon oxide. The capacitance C (farad) of the capacitor is 0.1 (4π ² f ² L) ⁻¹ ≦ C ≦ 10, where f (hertz) is the frequency of the high frequency power and L (Henry) is the inductance of the rotating shaft. (4π ² f ² L) ⁻¹
The deposited film forming apparatus according to claim 1, wherein: When the capacitance C (farad) of the capacitor is f (hertz) as the frequency of the high frequency power and L (Henry) is the inductance of the rotating shaft,
0.5 (4π ² f ² L) ⁻¹ ≦ C ≦ 5 (4π ² f ² L) ⁻¹
The deposited film forming apparatus according to claim 1, wherein:

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