JP2008214712A - Deposited film forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a deposited film forming device capable of improving the uniformity in the film thickness and film properties of a deposited film, and further capable of improving the film properties of the deposited film. <P>SOLUTION: In the device where a deposited film is formed on a cylindrical support by a plasma CVD (Chemical Vapor Deposition) process using: a gas introduction means composed of a plurality of gaseous starting material introduction tubes; an exhaust means performing exhaust from the side walls in a cylindrical reaction vessel; and a means of exciting a gaseous starting material by discharge energy, the exhaust directions in the circumferential direction within each gaseous starting material introduction tube and the cylindrical reaction vessel are the same number, and also, structures are not present in a region A which is the region where the circumferential direction is surrounded by the following I, II and II, and also, the axial direction corresponds to the cylindrical support: I is a straight line obtained by connecting the center of each gaseous starting material introduction tube and the center of the cylindrical support; II is a straight line obtained by connecting the center of the exhaust port closest viewed from each gaseous starting material introduction tube; and III is the inner wall of the cylindrical reaction vessel. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a deposited film on a substrate to be treated, especially a functional deposited film, for example, an amorphous or multi-layered film used for semiconductor devices, electrophotographic photoreceptors, line sensors for image input, imaging devices, photovoltaic elements, and the like. The present invention relates to a deposited film forming apparatus for forming a light receiving member using a non-single crystalline deposited film such as a crystal, and more particularly to a deposited film forming apparatus for forming a deposited film by a plasma CVD method.

  Conventionally, as an element member used for, for example, a semiconductor device, an electrophotographic photoreceptor device, an image input line sensor, an imaging device, a photovoltaic device, various other electronic elements, optical elements, etc., amorphous silicon such as hydrogen and halogen (for example, A deposited film for a semiconductor or the like composed of an amorphous material such as amorphous silicon (herein, amorphous refers to a non-single crystal) compensated for at least one of fluorine, chlorine and the like is proposed. Some of them are put to practical use.

  When this kind of deposited film is formed, it is necessary to make the deposited film thickness and film characteristics uniform, and the plasma is made uniform by a source gas supply method, a plasma CVD (Chemical Vapor Deposition) method, or the like. It is effective to rotate the means and the substrate to be processed on which the deposited film is formed in order to make the deposited film thickness and film characteristics uniform.

  Further, Patent Document 1 discloses an apparatus that defines a source gas supply means, an array of deposited film forming substrates, and an exhaust direction for the purpose of improving the utilization efficiency of the source gas and making the deposited film uniform. ing.

  Further, Patent Document 2 prescribes the source gas supply means, the material of the electrode component that blows out the source gas, and the conductance of the suction port near the periphery of the target object for the purpose of homogenizing the plasma processing. An apparatus is disclosed.

  Here, a schematic diagram of an example of a conventional deposited film forming apparatus 710 is shown in FIG. 7A is a longitudinal sectional view, and FIG. 7B is a transverse sectional view.

  The deposited film forming apparatus 710 includes a cylindrical reaction vessel 711 for forming a deposited film on the cylindrical support 712 by plasma treatment, a heater 713 for heating the cylindrical support 712, and a cylindrical reaction vessel. A substrate holder 717 for holding a cylindrical support 712 disposed in 711 and a source gas introduction pipe 714 for introducing source gas into the cylindrical reaction vessel 711 are provided.

  Further, the deposited film forming apparatus 710 has a mixing 723 with a mass flow controller (not shown) for adjusting the flow rate of the source gas, and a source gas inflow for adjusting the source gas supplied to the source gas introduction pipe 714. A valve 730, a cylindrical reaction vessel 711 to which high-frequency discharge power is supplied, and a matching box 715 having a high-frequency power source 716 and a matching circuit for supplying high-frequency power to the cylindrical reaction vessel 711 are provided.

  A high frequency power source 716 is electrically connected to the cylindrical reaction vessel 711 via a high frequency matching box 715.

  Further, a rotation support mechanism 705 that rotatably supports a substrate holder 717 that holds the cylindrical support 712 is provided at the lower portion of the cylindrical reaction vessel 711. The rotation support mechanism 705 includes a turntable 721 on which a base holder 717 is placed, a support shaft 722 that rotatably supports the turntable 721, and a motor 720 for rotating the turntable 721. Yes.

  The cylindrical support 712 is mounted on the base holder 717, and is rotatable with the base holder 717 by rotating the turntable 721 around the axis of the support shaft 722.

  The exhaust system provided in the deposited film forming apparatus 710 includes an exhaust pipe 728 communicating with an exhaust port 726 provided on the side wall of the cylindrical reaction vessel 711, a vacuum gauge 725 provided in the path of the exhaust pipe 728, an exhaust A main valve 727 and a vacuum pump 729 such as a rotary pump or a mechanical booster pump are provided, and the inside of the cylindrical reaction vessel 711 is maintained at a predetermined pressure.

  By forming the deposited film using the conventional deposited film forming apparatus configured as described above, it is possible to obtain a deposited film in which practical film characteristics and uniformity are ensured to some extent.

Conventionally, the above-described apparatus has been used to make the deposited film uniform. However, in recent years, with the digitization and colorization, the uniformity of the deposited film is required more than ever. Further, a deposited film having further improved electrophotographic characteristics has been demanded, and the layer configuration of the deposited film has been diversified. As a result, conditions for forming the deposited film have been complicated.
Japanese Patent Publication No. 5-32472 JP-A-8-153679

  However, in these conventional deposited film forming apparatuses described above, the layer configuration of the deposited film has been diversified in order to improve the electrophotographic characteristics as described above, resulting in complicated deposition film forming conditions. Therefore, in the conventional deposited film forming apparatus, it may be difficult to flow the source gas uniformly and stably for all the forming conditions.

  For example, in the above-described apparatus shown in FIG. 7, when a product requiring a relatively large area and a thick deposited film, such as an electrophotographic photoreceptor, is produced, a large amount of powdery by-products are generated when the deposited film is formed. To do. These by-products may be deposited on the surface of the aforementioned raw material gas introduction pipe depending on the processing conditions. If a large amount of by-products are deposited on the surface of the source gas introduction pipe, for example, changing the flow of the source gas may affect the film characteristics of the deposited film or the uniformity of the deposited film.

  In the conventional electrophotographic apparatus, as described above, there was no practical problem even when an electrophotographic photosensitive member made of a deposited film formed in a state where a change in the gas flow occurred during the formation of the deposited film. .

  However, for example, in recent high-quality color apparatuses, since gradation is improved, when the electrophotographic photoreceptor as described above is used, unevenness in electrophotographic characteristics of the electrophotographic photoreceptor is visually observed. May become noticeable.

  Furthermore, as a result of improvements in the optical exposure system, developing device, and transfer device in the electrophotographic apparatus to improve the image characteristics of the electrophotographic apparatus, the surface on which the deposited film is formed during film formation, which has not been a major problem until now It is required to suppress minute structural defects caused by dust adhering to the surface. In the following description, the “structural defect” refers to a defect grown from a foreign material such as dust attached to the surface of the deposited film.

  For example, in the case of an electrophotographic photoreceptor, this structural defect is confirmed as a hemispherical protrusion (hereinafter referred to as “spherical protrusion”) on the photoreceptor. When such spherical protrusions are present, when the photosensitive member is charged, electric charges are transferred from the spherical protrusions onto the substrate, and as a result, black spots or white spots appear on the electrophotographic image, resulting in an electrophotographic image quality. Is greatly impaired. Further, even in the case of other electronic devices, the movement of the carrier is hindered, causing a malfunction.

  Therefore, an object of the present invention is to provide a deposited film forming apparatus capable of improving the uniformity of the film thickness and film characteristics of the deposited film and further improving the film characteristics of the deposited film.

In order to achieve the above-described object, the deposited film forming apparatus according to the present invention comprises a cylindrical reaction vessel capable of depressurization, a means for installing a cylindrical support in the cylindrical reaction vessel, and the cylindrical support. Plasma CVD using a means for rotating the gas, a gas introduction means comprising a plurality of source gas introduction pipes, an exhaust means for exhausting from the side wall in the cylindrical reaction vessel, and a means for exciting the source gas by discharge energy In an apparatus for forming a deposited film on a cylindrical support by the method,
The source gas introduction pipe and the exhaust direction in the circumferential direction in the cylindrical reaction vessel are the same number, and there is no structure in the region A shown below.

Region A: The circumferential direction is surrounded by the following I, II, and III, and the axial direction corresponds to the cylindrical support. I The center of the cylindrical support is connected from the center of the source gas introduction pipe. Straight line
II A straight line connecting the center of the nearest exhaust port and the center of the cylindrical support as viewed from the source gas pipe
III Inner Wall of the Cylindrical Reaction Vessel As described above, the configuration of the present invention can improve the uniformity of the film characteristics and further improve the characteristics of the deposited film.

  This cause is presumed as follows.

  When the conventional deposited film forming apparatus shown in FIG. 7 is used and a product requiring a thick deposited film with a relatively large area, such as an electrophotographic photoreceptor, is manufactured as described above, A large amount of powdery by-products are generated, and these by-products may be deposited on the surface of the aforementioned raw material gas introduction pipe depending on the processing conditions. The cause of this is considered to be that if a structure, which is a raw material gas introduction pipe, is installed in the gas flow toward the exhaust port, the flow of the raw material gas is blocked by the structure and gas stagnation occurs. As a result, it is considered that the gas phase reaction is promoted and powdery by-products are deposited on the surface of the raw material gas introduction pipe.

When a large amount of by-products accumulates on the surface of the source gas introduction pipe,
1) By-products are also deposited in the vicinity of the gas discharge hole provided on the surface of the raw material gas, and the amount of raw material gas blown out from the gas discharge hole changes.

  2) A raw material gas is used to form a by-product on the surface of the raw material gas introduction pipe, and the thickness of the cylindrical support corresponding to the position is reduced.

  As described above, the situations 1) and 2) may occur.

  As a result, nonuniformity occurs in the gas flow, and nonuniformity of the deposited film in the bus line direction occurs.

  Therefore, by supplying the source gas from the side opposite to the exhaust port (for example, the three source gas introduction pipes in FIG. 7 are made one), powdery by-products are deposited on the surface of the source gas introduction pipe. However, the plasma formed in the circumferential direction of the cylindrical support may be nonuniform. As a result, the uniformity in the circumferential direction of the cylindrical support may be impaired.

  As described above, in the conventional deposited film forming apparatus, it may be difficult to achieve both the uniformity in the circumferential direction of the cylindrical support and the uniformity in the longitudinal direction.

  According to the present invention, the region A shown below has no structure.

Region A: The circumferential direction is surrounded by the following I, II, and III, and the axial direction corresponds to the cylindrical support. I The center of the cylindrical support is connected from the center of the source gas introduction pipe. Straight line
II A straight line connecting the center of the nearest exhaust port and the center of the cylindrical support as viewed from the source gas pipe
III Inner wall of the cylindrical reaction vessel Therefore, as described above, the flow of the raw material gas is prevented from being blocked by the structure, so that the by-product is prevented from being deposited on the surface of the raw material gas introduction pipe. Thus, the uniformity of gas flow is improved.

  This is because at least in the axial direction, the structure corresponding to the cylindrical support has no structure, so that the uniformity of gas flow can always be improved, particularly for the cylindrical support. It becomes composition.

  As a result, the uniformity of the deposited film, particularly in the busbar direction, is improved.

Furthermore, according to the present invention, in addition to the above-described configuration, the exhaust direction in the circumferential direction in the source gas introduction pipe and the cylindrical reaction vessel is the same number,
A plurality of source gas introduction pipes can be installed so as to surround the cylindrical support without causing a situation in which by-products are deposited on the surface of the source gas introduction pipe as in the prior art. Uniformity is improved. As a result, the circumferential uniformity of the deposited film can be improved.

  Furthermore, according to the present invention, the minute structural defects generated on the surface of the deposited film referred to as “spherical protrusion” described above can be greatly reduced, and the characteristics of the deposited film can be improved. This cause is presumed as follows.

  As described above, it is known that the spherical protrusion is generated by dust adhering to the film surface during the formation of the deposited film. As described above, the present invention improves the uniformity of the deposited film on the support. On the other hand, it is presumed that the uniformity of the deposited film other than the support such as the cylindrical reaction vessel is also improved. As a result, since the distortion such as internal stress in the deposited film, which has conventionally occurred, is reduced, the adhesion of the deposited film is improved, and the film peeling during the formation of the deposited film is reduced.

  Further, in the conventional apparatus, the flow of the raw material gas is blocked by the structure. As a result, the gas phase reaction is promoted and the production of by-products is promoted. This by-product is in a powder form and is considered to float in the discharge space relatively easily. It is considered that the floating by-product reaches the support with a certain probability and becomes a dust source. According to the present invention, since the flow of the raw material gas is blocked by the structure as described above, the production of by-products is reduced.

  As described above, it is considered that the adhesion properties of the deposited film other than the support are improved, and the generation of by-products is further reduced, so that the properties of the deposited film are improved.

  The deposited film forming apparatus of the present invention makes it possible to achieve both the uniformity in the circumferential direction of the cylindrical support and the uniformity in the longitudinal direction.

  Furthermore, according to the present invention, the characteristics of the deposited film can be improved.

According to the present invention, the source gas introduction pipe and the exhaust direction in the circumferential direction in the cylindrical reaction vessel are the same number, and
In the region A shown below, it is possible to improve the uniformity of the film characteristics and further improve the characteristics of the deposited film by setting the structure without structures.

Region A: The circumferential direction is surrounded by the following I, II, and III, and the axial direction corresponds to the cylindrical support. I The center of the cylindrical support is connected from the center of the source gas introduction pipe. Straight line
II A straight line connecting the center of the nearest exhaust port and the center of the cylindrical support as viewed from the source gas pipe
III Inner wall of the cylindrical reaction vessel

  Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 shows an example of a deposited film forming apparatus for manufacturing an electrophotographic photoreceptor by an RF (Radio Frequency) -CVD (Chemical Vapor Deposition) method using a high frequency of 13.56 [MHz] band of the present invention. It is the longitudinal cross-sectional view which showed typically. 1A is a longitudinal sectional view, and FIG. 1B is a transverse sectional view.

  The deposited film forming apparatus 110 includes a cylindrical reaction vessel 111 for forming a deposited film on the cylindrical support 112 by plasma treatment, a heater 113 for heating the cylindrical support 112, and a cylindrical reaction vessel. A support holder 117 for holding a cylindrical support 112 arranged in the base 111, and source gas introduction pipes 114-1 and 114-2 for introducing a source gas into the cylindrical reaction vessel 111. .

  The deposited film forming apparatus 110 adjusts the raw material gas supplied to the mixing gas 123 and the raw material gas introduction pipes 114-1 and 114-2 through a mass flow controller (not shown) for adjusting the flow rate of the raw material gas. A raw material gas inflow valve 130 is provided.

  The deposited film forming apparatus 110 includes a cylindrical reaction vessel 111 to which high-frequency discharge power is supplied, a high-frequency power source 116 for supplying high-frequency power to the cylindrical reaction vessel 111, and a matching box 115 having a matching circuit. I have.

  The cylindrical support 112 only needs to have a material according to the purpose of use. As the material of the cylindrical support 112, for example, copper, aluminum, gold, silver, platinum, lead, nickel, cobalt, iron, chromium, molybdenum, titanium, stainless steel, and the like are preferable because of their good electrical conductivity. However, aluminum is optimal in consideration of workability and manufacturing cost. Moreover, as aluminum which forms the cylindrical support body 112, it is preferable to use either an Al-Mg type alloy or an Al-Mn type alloy, for example.

  The heater 113 for heating is provided inside the base holder 117. The heating heater 113 may be a heating element that can be used in a vacuum. Specifically, an electrical resistance heating element such as a sheath heater, a plate heater, a ceramic heater, or a carbon heater, a halogen lamp, or an infrared lamp. Examples of the heat radiation lamp heating element such as a heat radiation lamp and the like, and a heating element by heat exchange means using a liquid, gas, or the like as a heat medium, are examples. As the surface material of the heater 113, metals such as stainless steel, nickel, aluminum, and copper, ceramics, heat resistant polymer resins, and the like can be used.

  A high frequency power supply 116 is electrically connected to the cylindrical reaction vessel 111 via a high frequency matching box 115. The cylindrical reaction vessel 111 is insulated from the lower plate 118 and the upper lid 119 of the cylindrical reaction vessel 111 serving as the ground surface by an insulator 131 made of ceramics.

  Further, a rotation support mechanism 105 that rotatably supports a support holder 117 that holds the cylindrical support 112 is provided in the lower part of the cylindrical reaction vessel 111. The rotation support mechanism 105 includes a turntable 121 on which a support holder 117 is placed, a support shaft 122 that supports the turntable 121, and a motor 120 that rotates the turntable 121.

  The cylindrical support 112 is mounted on the support holder 117 and rotated about the support shaft 122 together with the turntable 121.

  The exhaust system provided in the deposited film forming apparatus 110 is provided in each path of the exhaust pipes 128A and 128B and the exhaust pipes 128A and 128B communicated with the exhaust ports 126A and 126B provided on the side wall of the cylindrical reaction vessel 111. Vacuum gauges 125A and 125B, exhaust main valves 127A and 127B, and vacuum pump units 129A and 129B such as a rotary pump and a mechanical booster pump, for example, to maintain the inside of the cylindrical reaction vessel 111 at a predetermined pressure. .

  The exhaust pipes 128A and 128B are connected to the side surface of the cylindrical reaction vessel 111 via an insulator 131. The exhaust port 126A and the exhaust port 126B are provided at positions opposed to the cylindrical support 112 by 180 °. In this case, the exhaust direction is two directions, the 126A direction and the 126B direction. That is, the exhaust direction in the present invention refers to the direction from the center of the cylindrical support to the exhaust port.

  The source gas introduction pipes 114-1 and 114-2 are provided at positions that are 180 ° relative to the cylindrical support 112. Further, the source gas introduction pipes 114-1 and 114-2 are installed at the same distance from the exhaust port 126A and the exhaust port 126B, respectively.

As described above, by arranging the source gas introduction pipes 114-1, 114-2 and the exhaust ports 126A, 126B,
1: The source gas introduction pipe and the exhaust direction in the circumferential direction in the cylindrical reaction vessel 111 are set to the same number.
Furthermore, the area A shown below has no structure.
Region A: The circumferential direction is surrounded by the following I, II, and III, and the axial direction corresponds to the cylindrical support. I The center of the cylindrical support is connected from the center of the source gas introduction pipe. Straight line
II A straight line connecting the center of the nearest exhaust port and the center of the cylindrical support as viewed from the source gas pipe
III The inner wall region A of the cylindrical reaction vessel will be described with reference to FIG. FIG. 2 is a partial cross-sectional view of the deposited film forming apparatus 110 shown in FIG.

  First, the source gas introduction pipe 114-2 will be described.

  In FIG. 2, a straight line I is a straight line connecting the center of the cylindrical support 112 from the center of the source gas introduction pipe 114-2.

  For convenience of explanation, the straight line II is divided into II-1 to II-2. In the deposited film forming apparatus 110 shown in FIG. 1, the source gas pipes 114-1 and 114-2 are installed at equal distances from the exhaust ports 126A and 126B. Therefore, when viewed from the source gas introduction pipe 114-2, the nearest exhaust ports are the exhaust port 126A and the exhaust port 126B. First, in FIG. 2, a straight line II-1 is a straight line connecting the center of the nearest exhaust port 126B and the center of the cylindrical support 112, as viewed from the raw material gas pipe 114-2, and the raw material gas introduction pipe 114-2. With regard to the above, a region (shown as a region A-1) surrounded by the straight line I, the straight lines II-1 and III (inner wall of the cylindrical reaction vessel) is first included in the region A.

  Further, as described above, the source gas introduction pipe 114-2 includes the exhaust port 126A as the nearest exhaust port. When a straight line connecting the center of the exhaust port 126A and the center of the cylindrical support 112 is defined as a straight line II-2, the straight line I, the straight lines II-2, and III ( A region (shown as region A-1) surrounded by the inner wall of the cylindrical reaction vessel is also included in region A.

  Next, the source gas introduction pipe 114-1 will be described.

  As in the case of the source gas introduction pipe 114-2 described above, a straight line connecting the center of the cylindrical support 112 from the center of the source gas introduction pipe 114-1 is a straight line I.

  The straight line II is also divided into II-3 to II-4 for convenience of explanation. Similar to the source gas introduction pipe 114-2, the nearest exhaust ports are the exhaust port 126A and the exhaust port 126B. Therefore, a straight line connecting the center of the nearest exhaust port 126B and the center of the cylindrical support 112 is defined as a straight line II-3, and further, the center of the exhaust port 126A and the center of the cylindrical support 112 are connected. When the straight line is defined as a straight line II-4, with respect to the raw material gas introduction pipe 114-1, a region (region A-) surrounded by the straight line I, the straight line II-3, and III (the inner wall of the cylindrical reaction vessel). 3), a region surrounded by the straight line I, the straight line II-4, and III (inner wall of the cylindrical reaction vessel) (shown as a region A-4) is included in the region A.

  Further, the axial range of the region A is a range corresponding to the cylindrical support 112 (referred to as a range A-5, not shown).

  Therefore, in the deposited film forming apparatus of FIG. 1, the region A is the above-described region (A-1 + A-2 + A-3 + A-4) × range A-5. However, the cylindrical support 112 and the source gas introduction pipes 114-1 and 114-2 are excluded from the region A.

  An example of a procedure of a method for forming a deposited film using the deposited film forming apparatus 110 configured as described above will be described below.

  A support holder 117 to which a cylindrical support 112 is mounted is installed in the cylindrical reaction vessel 111, and the inside of the cylindrical reaction vessel 111 is exhausted by the vacuum pump units 129A and 129B. Subsequently, a raw material gas necessary for heating the cylindrical support 112, for example, a gas such as Ar or He, is introduced into the cylindrical reaction vessel 111 via the mixing 123 and the raw material gas introduction pipes 114-1 and 114-2. Using the vacuum pump units 129A and 129B and the exhaust main valves 127A and 127B, the inside of the cylindrical reaction vessel 111 is adjusted while looking at the vacuum gauges 125A and 125B so as to have a predetermined pressure. As an adjustment at this time, the exhaust ports such as the opening degrees of the exhaust main valves 127A and 127B and the exhaust capabilities such as the rotation speeds of the vacuum pump units 129A and 129B are made substantially equal to each other, thereby exhausting from the exhaust ports 126A and 126B. Adjust the gas volume to be approximately equal.

  Next, after reaching a predetermined pressure, the temperature of the cylindrical support 112 is set to about 200 [° C.] to 450 [° C.], more preferably about 250 [° C.] to 350 [° C.] by the heater 113 for heating. To control the temperature.

  After the preparation for forming the deposited film is completed by the above procedure, the deposited film is formed on the cylindrical support 112.

  That is, the raw material gas for heating and the raw material gas for forming the deposited film are mixed and introduced through the mixing 123 so that the raw material gas is adjusted to have a desired flow rate. At that time, the mechanical booster pumps of the vacuum pump units 129A and 129B are checked while checking the vacuum gauges 125A and 125B so that the inside of the cylindrical reaction vessel 111 has a desired pressure of about 13.3 [mPa] to 1330 [Pa]. Adjust the rotation frequency. At this time, the opening degree of the exhaust main valves 127A and 127B and the rotation frequency of the mechanical booster pumps of the vacuum pump units 129A and 129B are substantially equal to each other, thereby reducing the amount of gas exhausted from the exhaust ports 126A and 126B. Adjust to be approximately equal.

  After the pressure in the cylindrical reaction vessel 111 is stabilized, the high frequency power supply 116 is set to a desired power, for example, about 13.56 [MHz] to 45 [MHz], for example, RF having a frequency of 13.56 [MHz]. A high frequency glow discharge is generated by supplying high frequency power to the cylindrical reaction vessel 111 via the high frequency matching box 115 using a power source.

  With this discharge energy, the raw material gas introduced into the cylindrical reaction vessel 111 is decomposed, and a deposited film mainly containing desired silicon atoms is formed on the cylindrical support 112.

  In order to form a uniform deposited film, the cylindrical support 112 is rotated at the same time as forming the deposited film or at the stage of heating the cylindrical support 112. The motor 120 is rotated and rotated at a rotation speed of about 1 [rpm] to 30 [rpm], for example, 1 [rpm]. By doing so, a uniform deposited film is formed in the circumferential direction of the cylindrical support 112.

  By repeatedly forming the deposited film as described above, for example, a multi-layered electrophotographic photosensitive member having a desired deposited film is formed on the outer peripheral surface of the cylindrical support 112.

Next, after the deposited film is formed, the supply of the source gas and the high frequency power is stopped, and the inside of the cylindrical reaction vessel 111 is exhausted. Thereafter, the inside of the cylindrical reaction vessel 111 and the raw material gas introduction pipes 114-1 and 114-2 is purged using a purge gas, for example, at least one of an inert gas such as Ar and N ₂ . After the purge process is completed, the inside of the cylindrical reaction vessel 111 is returned to atmospheric pressure using at least one of an inert gas such as Ar and N ₂ gas, and the cylindrical substrate 112 is taken out from the cylindrical reaction vessel 111.

Thereafter, the deposited by-product such as polysilane is subjected to a cleaning process. As a procedure at that time, instead of the cylindrical substrate 112, a cleaning dummy substrate (not shown) having the same shape is installed in the cylindrical reaction vessel 111, and the cylindrical reaction vessel 111 is formed by the vacuum pump units 129A and 129B. Exhaust inside. Subsequently, a gas necessary for the cleaning process, such as a mixed gas of Ar and ClF ₃ , is introduced into the cylindrical reaction vessel 111 through the mixing 12 3 and the source gas introduction pipes 114-1 and 114-2, and the vacuum pump unit 129 A , 129B and exhaust main valves 127A, 127B are adjusted while looking at the vacuum gauges 125A, 125B so that the inside of the cylindrical reaction vessel 111 becomes a predetermined pressure.

  After the pressure in the cylindrical reaction vessel 111 is stabilized, the high frequency power supply 116 is set to a desired power, for example, about 13.56 [MHz] to 45 [MHz], for example, RF having a frequency of 13.56 [MHz]. A high frequency glow discharge is generated by supplying high frequency power to the cylindrical reaction vessel 111 via the high frequency matching box 115 using a power source. With this discharge energy, the cleaning gas introduced into the cylindrical reaction vessel 111 is decomposed, and the inside of the cylindrical reaction vessel 111 is cleaned.

Next, the supply of high frequency power is stopped after the cleaning process, and the inside of the cylindrical reaction vessel 111 is evacuated. Thereafter, the purging process by using a cylindrical reaction vessel 111 and the raw material gas introduction pipe introducing tube 114-1 purge, for example at least one inert gas and N _2, such as Ar. After the purge process is completed, the inside of the cylindrical reaction vessel 111 is returned to atmospheric pressure by using at least one of an inert gas such as Ar and N ₂ gas, and a dummy substrate for cleaning (not shown) is removed from the inside of the cylindrical reaction vessel 111. Take out.

  The material of the source gas introduction pipes 114-1 and 114-2 of the present invention can be used in a vacuum, any material can be used as long as it does not disturb the discharge, has practical strength, and does not contaminate the discharge space. Among them, preferred are glass, ceramics and the like. In particular, alumina ceramics are suitable for the present invention.

  The number of source gas introduction pipes 114 of the present invention is not particularly limited as long as it is the same as the exhaust direction, but 2 to 8 is suitable.

  Further, the size of the gas discharge hole provided in the source gas introduction pipe 114 is not particularly limited. However, since the plasma may be non-uniform if it is too large or too small, the diameter is preferably 0. A range of 1 to 3 mm, optimally 0.2 to 2 mm, is suitable for the present invention.

  There is no particular limitation on the number of gas discharge holes, but if it is too much or too little, the plasma may become non-uniform. The range of 30 to 100 is suitable for the present invention.

  There are no particular restrictions on the intervals at which the gas discharge holes are provided (gas discharge hole intervals in the longitudinal direction of the raw material gas introduction pipe). It is desirable to provide it.

  The direction of the gas discharge holes provided in the source gas introduction pipe 114 will be described with reference to FIG. FIG. 3 is a partial cross-sectional view of the deposited film forming apparatus 110 shown in FIG. 1 and an enlarged view of the source gas introduction pipe 114-2.

  The direction of the gas discharge hole provided in the source gas introduction pipe 114 is not particularly limited, but is surrounded by the following straight lines A and B from the viewpoint of the usage efficiency of the source gas and the uniformity of the deposited film. It is preferable to point in the direction.

Straight line A: A straight line obtained by drawing a tangent to the cylindrical support from the center of the source gas introduction pipe. Straight line B: A straight line connecting the center of the exhaust gas direction from the center of the source gas introduction pipe. As shown in FIG. 3, it is a straight line obtained by drawing a tangent to the cylindrical support 112 from the center of the source gas introduction pipe 114-2.

  As shown in FIG. 3, the straight line B is a straight line that connects the center of the source gas introduction pipe 114-2 to the center of the exhaust direction (directions 126A and 126B). At this time, the center in the exhaust direction is a point that becomes the center of the exhaust ports 126A and 126B on the inner surface of the cylindrical reaction vessel 111.

  Providing gas discharge holes on the source gas introduction pipe 114-2 (thick line portion in the enlarged view) surrounded by the adjacent straight lines A and B can improve the utilization efficiency of the source gas and the uniformity of the deposited film. From the aspect, it is preferable.

  When the gas discharge hole is directed toward the cylindrical support from the straight line A, a minute non-uniformity corresponding to the pitch of the gas discharge hole may occur depending on the deposition film forming condition. When the gas discharge hole is directed to the cylindrical reaction vessel side from the straight line B, the amount of the source gas deposited on the wall surface of the cylindrical reaction vessel increases, and the ratio of the source gas deposited on the cylindrical support surface is relatively descend. As a result, the utilization efficiency of the raw material gas may be reduced.

  The straight line A and straight line B have been described with respect to the raw material gas introduction pipe 114-2, but the straight line A and straight line B also exist in the raw material gas introduction pipe 114-1.

  With respect to the installation position of the source gas introduction pipe 114, there is no particular limitation as long as it is installed in the cylindrical reaction vessel 111 so that there is no structure in the nearest exhaust direction as seen from the source gas introduction pipe 114. However, it is preferable that the source gas introduction pipes 114 and the exhaust direction are provided alternately at equal intervals in the circumferential direction from the viewpoint of improving the characteristics of the deposited film and uniformity in the circumferential direction.

In the present invention, the source gas used when forming the deposited film includes silane (SiH ₄ ), disilane (Si ₂ H ₆ ), silicon tetrafluoride (SiF ₄ ), disilicon hexafluoride (Si ₂ F ₆ ), and the like. It is also effective to use a raw material gas for forming amorphous silicon or a mixed gas thereof. It is also effective to use hydrogen (H ₂ ), argon (Ar), helium (He) or the like as the dilution gas. Further, as a gas for improving characteristics such as changing the band gap width of the deposited film, a gas containing nitrogen atoms such as nitrogen (N ₂ ) and ammonia (NH ₃ ), oxygen (O ₂ ), nitrogen monoxide (NO), Nitrogen dioxide (NO ₂ ), dinitrogen oxide (N ₂ O), carbon monoxide (CO), carbon dioxide (CO ₂ ) and other oxygen atoms, methane (CH ₄ ), ethane (C ₂ H ₆ ), Fluorine compounds such as hydrocarbons such as ethylene (C ₂ H ₄ ), acetylene (C ₂ H ₂ ), propane (C ₃ H ₈ ), germanium tetrafluoride (GeF ₄ ), nitrogen fluoride (NF ₃ ), or the like It is also effective to use a mixed gas of

For the purpose of doping treatment, it is also effective to introduce a dopant gas such as diborane (B ₂ H ₆ ), boron fluoride (BF ₃ ), or phosphine (PH ₃ ) into the discharge space at the same time.

Examples of the cleaning gas used during the cleaning process include CF ₄ , CF ₄ / O ₂ , SF ₆ , and ClF ₃ (chlorine trifluoride). In this embodiment, the cleaning time is shortened. Effective ClF ₃ (chlorine trifluoride) is used. In the present embodiment, it is effective to adjust the concentration by using an inert gas for dilution in order to adjust the concentration of the cleaning gas. As the inert gas to be introduced, for example, He , Ne, and Ar, and Ar is preferably used.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited at all by these.

  Using the deposited film forming apparatus shown in FIG. 1, amorphous silicon deposition having the layer configuration shown in FIG. 4 is performed on a cylindrical support 112 made of aluminum having a diameter of 80 mm, a length of 358 mm, and a thickness of 3 mm under the conditions shown in Table 1. A film was formed (hereinafter abbreviated as an electrophotographic photosensitive member). In FIG. 4, reference numeral 401 indicates a cylindrical support, reference numeral 402 indicates a lower blocking layer, reference numeral 403 indicates a photoconductive layer, reference numeral 404 indicates an intermediate layer 1, reference numeral 405 indicates an upper blocking layer, and reference numeral 406 indicates an intermediate layer 2. Reference numeral 407 denotes a surface layer.

  In the present example, the position of the source gas blowing hole provided on the source gas introduction pipe 114 was changed as shown in Table 2 below.

(Evaluation method of electrophotographic characteristics)
FIG. 5 shows a schematic diagram of a copying machine for evaluating the characteristics of an electrophotographic photosensitive member. In FIG. 5, there are a main charger 502, a potential sensor 503, a developing device 504, a transfer charger 505 (a), a separation charger 505 (b), and a cleaning roller 506 around the electrophotographic photosensitive member 501 that rotates clockwise. A cleaner 510 having a cleaning blade 507, a pre-exposure 508, and the like are disposed. The latent image forming exposure 509 is provided between the main charger 502 and the potential sensor 503.

  When measuring the characteristics of the electrophotographic photosensitive member, the developing device 504 and the cleaner 510 are removed, and a potential probe (not shown) that can measure the electrophotographic characteristics of the electrophotographic photosensitive member in the axial direction is attached instead of the developing device 504. The electrophotographic characteristics of the electrophotographic photosensitive member are measured.

  Using the electrophotographic process configured in this way, the electrophotographic characteristics were evaluated according to the following criteria.

Evaluation of “Vd bus line unevenness”, “Vd circumferential unevenness”, “white spot”, “deposition rate”, and “overall evaluation” was performed as follows on the electrophotographic photosensitive member thus prepared.
・ "Vd bus unevenness"
Surface potential meter (TREK Model 344) with a process speed of 265 mm / sec, pre-exposure (LED with a wavelength of 660 nm) light quantity of 4 μJ / cm ^2, and the surface potential at the middle position in the direction of the bus of the electrophotographic photosensitive member set at the developer position The current value of the charger is adjusted to 450 V (dark potential) with the potential sensor. Thereafter, the measurement probe was measured at 12 points in the axial direction from the end of the electrophotographic photosensitive member, and the maximum-minimum value of the 12 points was evaluated as Vd bus line unevenness. And the relative evaluation which made the result of the following comparative examples 1 100 was performed, and it evaluated as follows.

100 or less 95 or more △
94 or less 85 or more ○
84 or less ◎
・ "Vd circumference unevenness"
In the Vd bus line irregularity, the fluctuation of the surface potential at the time of measuring each point in the axial direction was measured, and the maximum value of the fluctuation of 12 points was evaluated as the Vd circumferential irregularity. And the relative evaluation which made the result of the following comparative examples 1 100 was performed, and it evaluated as follows.

100 or less 95 or more △
94 or less 85 or more ○
84 or less ◎
・ "Black Potty"
An image having a transmission density of 1.8 was prepared by adjusting the charging voltage, the developing bias, etc., and the number of white spots having a diameter of 0.2 mm or more within a certain area of the image was evaluated. And the relative evaluation which made the result of the following comparative examples 1 100 was performed, and it evaluated as follows.

100 or less 80 or more △
79 or less 60 or more ○
59 or less ◎
・ "Deposition rate"
The total film thickness (total thickness of all layers) of the electrophotographic photosensitive member with the layer structure shown in Table 1 is 23.6μ, but with the necessary deposition film formation time, the deposition rate And

  The method for measuring the total film thickness was as follows.

  Using an eddy current film thickness meter (manufactured by Kett Science Laboratory), the film thickness was measured at 12 points in the axial direction from the end of the electrophotographic photosensitive member, and the average value was taken as the total film thickness. And the relative evaluation which made the result of the following comparative examples 1 100 was performed, and it evaluated as follows.

100 or less 96 or more △
95 or less 86 or more ○
85 or less ◎
·"Comprehensive evaluation"
In each evaluation of “Vd bus line unevenness”, “Vd circumferential unevenness”, “white spot”, and “deposition rate”,
All ◎ ◎
◎ and 〇 Mixed 〇 All △ △
The obtained results are shown in Table 3.

(Comparative Example 1)
7 using the deposited film forming apparatus shown in FIG. 7 on the cylindrical support 712 made of aluminum having a diameter of 80 mm, a length of 358 mm, and a wall thickness of 3 mm under the conditions shown in Table 1 The body was made.

  The produced electrophotographic photosensitive member was evaluated in the same manner as in Example 1, and the results obtained are shown in Table 3.

表３の結果から、原料ガス導入管と、前記円筒状反応容器内の円周方向における排気方向は、同一の数で、かつ下記に示す領域Aには、構造物が無い構成の堆積膜形成装置により、堆積膜を形成することで、堆積膜の均一性、堆積膜の膜特性が向上し、かつ堆積速度が向上することが判った。

From the results of Table 3, the deposition gas formation with the same number of the source gas introduction pipe and the exhaust direction in the circumferential direction in the cylindrical reaction vessel, and no structure in the region A shown below. It has been found that forming a deposited film with the apparatus improves the uniformity of the deposited film, the film properties of the deposited film, and improves the deposition rate.

Region A: The circumferential direction is surrounded by the following I, II and III, and the axial direction corresponds to the cylindrical support. I The center of the cylindrical support is connected from the center of the source gas introduction pipe. Straight line
II A straight line connecting the center of the nearest exhaust port and the center of the cylindrical support as viewed from the source gas pipe
III Inner wall of the cylindrical reaction vessel Further, as a raw material gas introduction pipe, adjacent straight lines A (straight line obtained by tangent to the cylindrical support from the center of the raw material gas introduction pipe) and straight line B (raw material gas introduction pipe) By using a material gas blowout hole in a direction surrounded by a straight line connecting the center of the exhaust direction and the center of the exhaust direction, the uniformity of the film characteristics of the deposited film and the deposition rate are further improved. It turns out that it improves.

  The reason is presumed as follows.

  The Vd bus line irregularity of the electrophotographic photosensitive member prepared under condition 4 (the source gas outlet hole is located on the source gas introduction pipe on the side of the cylindrical support from the straight line A) is detailed. As a result, it was found that the surface potential changed corresponding to the position of the blowout hole of the source gas. Presuming from this result, the source gas blowing holes are directed toward the cylindrical support from the straight line A, so that the film on the cylindrical support is not sufficiently diffused in the direction of the bus of the source gas. Is deposited. As a result, it is considered that unevenness slightly corresponding to the position of the blowing hole of the source gas occurs.

  Moreover, the deposition rate is slightly lowered by setting the condition 5 (the source gas outlet hole is located on the source gas introduction pipe on the side of the cylindrical reaction vessel from the straight line B). Is seen. This is presumably because the amount of by-products deposited on the inner wall surface of the cylindrical reaction vessel increased, and as a result, the proportion of the source gas contributing to film deposition on the cylindrical support decreased.

  An electrophotographic photosensitive member was produced in the same manner as in Example 1 using the deposited film forming apparatus shown in FIG.

  The deposited film forming apparatus in FIG. 6 will be described.

  FIG. 6 shows an example of a deposited film forming apparatus for manufacturing an electrophotographic photoreceptor by an RF (Radio Frequency) -CVD (Chemical Vapor Deposition) method using a high frequency of 13.56 [MHz] band of the present invention. It is the longitudinal cross-sectional view which showed typically. 6A is a longitudinal sectional view, and FIG. 6B is a transverse sectional view.

  The deposited film forming apparatus 610 includes a cylindrical reaction vessel 611 for forming a deposited film on the cylindrical support 612 by plasma processing, a heater 613 for heating the cylindrical support 612, and a cylindrical reaction vessel. A support holder 617 for holding a cylindrical support 612 disposed in 611, and source gas introduction pipes 614-1, 614-2, 614-3 for introducing a source gas into the cylindrical reaction vessel 611, 614-4.

  The deposited film forming apparatus 610 includes a mixing 623 with a mass flow controller (not shown) for adjusting the flow rate of the source gas, and source gas introduction pipes 614-1, 614-2, 614-3, 614- 4 is provided with a raw material gas inflow valve 630 for adjusting the raw material gas supplied to 4.

  The deposited film forming apparatus 610 includes a cylindrical reaction vessel 611 to which high-frequency discharge power is supplied, a high-frequency power source 616 for supplying high-frequency power to the cylindrical reaction vessel 511, and a matching box 615 having a matching circuit. I have.

  A high frequency power supply 616 is electrically connected to the cylindrical reaction vessel 611 via a high frequency matching box 615. The cylindrical reaction vessel 611 is insulated from the lower plate 618 and the upper lid 619 of the cylindrical reaction vessel 611 that are ground surfaces by an insulator 631 made of ceramics.

Further, a rotation support mechanism 605 that rotatably supports a support holder 617 that holds the cylindrical support 612 is provided at the lower portion of the cylindrical reaction vessel 611. The rotation support mechanism 605 includes a turntable 621 on which a support holder 617 is placed, a support shaft 622 that supports the turntable 621, and a motor 620 that rotates the turntable 621.
The cylindrical support 612 is mounted on the support holder 617 and rotated about the support shaft 622 together with the turntable 621.

  The exhaust system provided in the deposited film forming apparatus 610 includes exhaust pipes 628A, 628B, 628C, 628D communicated with exhaust ports 626A, 626B, 626C, 626D provided on the side wall of the cylindrical reaction vessel 611, and exhaust pipes 628A, Vacuum gauges 625A, 625B, 625C, 625D and exhaust main valves 627A, 627B, 627C, 627D provided in each path of 628B, 628C, 628D, and vacuum pump unit 629 such as a rotary pump, mechanical booster pump, etc. And the inside of the cylindrical reaction vessel 611 is maintained at a predetermined pressure.

  The exhaust pipes 628A, 628B, 628C, and 628D are connected to the side surface of the cylindrical reaction vessel 611 via an insulator 631. The exhaust ports 626A, 626B, 626C, and 626D are provided at positions shifted by 90 °. In this case, the exhaust directions are four directions of the 626A direction, the 626B direction, the 626C direction, and the 626D direction.

  The source gas introduction pipes 614-1, 614-2, 614-3, 614-4 are provided at positions shifted by 90 °. Further, the source gas introduction pipe 614-1 is installed at the same distance from the exhaust ports 626D and 626A. The source gas introduction pipe 614-2 is installed at the same distance from the exhaust ports 626A and 626B. The source gas introduction pipe 614-3 is installed at the same distance from the exhaust ports 626B and 626C. Source gas introduction pipe. 614-4 is installed at the same distance from the exhaust ports 626C and 626D.

As described above, by arranging the source gas introduction pipes 614-1, 614-2, 614-3, 614-4 and the exhaust ports 626A, 626B, 626C, 626D,
1: The source gas introduction pipe and the exhaust direction in the circumferential direction in the cylindrical reaction vessel 111 are set to the same number.
further
2: It is set so that there is no structure in the cylindrical reaction vessel 111 in the nearest exhaust direction as seen from the source gas introduction pipe.

3: The source gas introduction pipes and the exhaust direction are alternately arranged at equal intervals in the circumferential direction. Regarding the source gas blowing holes, the cross-sectional position is surrounded by the straight line A and the straight line B below. The center of the blowout hole is located in the center of the region.

Straight line A: Straight line drawn from the center of the source gas introduction pipe to the cylindrical support, Straight line B: Straight line connecting the center of the exhaust direction from the center of the source gas introduction pipe On the source gas introduction pipe, The axial position was 20 mm pitch, and the upper and lower outlet hole spacing was 440 mm. The hole diameter was 0.5 mm.

  A method of forming a deposited film using the deposited film forming apparatus 610 configured as described above is the same as that of the deposited film forming apparatus 110 described above.

  Evaluation similar to Example 1 was performed about the produced electrophotographic photoreceptor.

  The results obtained are shown in Table 3.

  From the results of Table 3, the source gas introduction pipe and the exhaust direction in the circumferential direction in the cylindrical reaction vessel are the same number, and at least the cylinder in the exhaust direction closest to the source gas pipe The deposited film is formed in a region corresponding to the cylindrical support by a deposited film forming apparatus having no structure in the cylindrical reaction vessel, thereby improving the uniformity of the deposited film and the film characteristics of the deposited film. It was also found that the deposition rate was improved. Further, it has been found that even if the source gas introduction pipe is arranged so as to surround the cylindrical support, the uniformity in the circumferential direction can be further improved while improving the uniformity in the busbar direction.

The typical sectional view showing an example of the deposited film forming device of the present invention. The typical sectional view showing an example of the deposited film forming device of the present invention. The typical sectional view showing an example of the deposited film forming device of the present invention. The schematic diagram which shows an example of the laminated constitution of an a-Si electrophotographic photoreceptor. 2 is a schematic view of a copying machine for evaluating electrophotographic photosensitive member characteristics. FIG. The typical sectional view showing an example of the deposited film forming device of the present invention. Schematic sectional view showing an example of a conventional deposited film forming apparatus.

Explanation of symbols

110, 610, 710 Deposited film forming equipment
111, 611, 711 Cylindrical reaction vessel
112, 612, 712 Cylindrical support
113, 613, 713 Heater for support heating
114-1 to 114-2, 614-1 to 614-4, 714 Source gas introduction pipe
115, 615, 715 High-frequency matching box
116, 616, 716 High frequency power supply
117, 617, 717 Support holder
118, 618, 718 Base plate
120, 620, 720 motor
121, 621, 721 cradle
122, 622, 722 rotation axis
123, 623, 723 mixing
125A to 125B, 625A to 625D, 725 Vacuum gauge
127A to 127B, 627A to 627D, 727 Exhaust valve
128A to 128B, 628A to 628D, 728 Exhaust piping
129A to 129B, 629, 729 Vacuum pump unit
131, 631, 731 Insulator
401 Cylindrical support
402 Lower blocking layer
403 photoconductive layer
404 Middle layer 1
405 Upper blocking layer
406 Middle layer 2
407 Surface layer

Claims (3)

In a cylindrical reaction vessel that can be depressurized,
Means for installing a cylindrical support in the cylindrical reaction vessel;
Means for allowing rotation of the cylindrical support;
A gas introduction means comprising a plurality of source gas introduction pipes;
Exhaust means for exhausting from the side wall in the cylindrical reaction vessel;
In an apparatus for forming a deposited film on the cylindrical support by a plasma CVD method using means for exciting the source gas by discharge energy,
Deposition by the plasma CVD method characterized in that the source gas introduction pipe and the exhaust direction in the circumferential direction in the cylindrical reaction vessel are the same number, and there is no structure in the region A shown below. Film forming device.
Region A: The circumferential direction is surrounded by the following I, II, and III, and the axial direction corresponds to the cylindrical support. I The center of the cylindrical support is connected from the center of the source gas introduction pipe. Straight line
II A straight line connecting the center of the nearest exhaust port and the center of the cylindrical support as viewed from the source gas pipe
III Inner wall of the cylindrical reaction vessel 2. The deposited film forming apparatus according to claim 1, wherein the source gas introduction pipe has a source gas blowing hole in a direction surrounded by the following straight line A and straight line B. 3.
Straight line A: straight line B: tangent to the cylindrical support from the center of the raw material gas introduction pipe, straight line B: straight line connecting the center of the exhaust direction from the center of the raw material gas introduction pipe   3. The deposited film forming apparatus according to claim 1, wherein the source gas introduction pipe and the exhaust direction are provided alternately at equal intervals in the circumferential direction.

Images