JP2009108370A - Deposited film forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a deposited film forming apparatus which can form a deposited film having highly uniform film thickness and film properties and few image defects with good productivity. <P>SOLUTION: The deposited film forming apparatus is configured in such a way that both end parts of a cylindrical substrate (not shown in figure) are each electrically connected to a rotary stage (not shown in figure) being a standard grounding part of the deposited film forming apparatus so as to be grounded. An impedance regulating part 140 is provided between at least one end part of the both end parts of the cylindrical substrate and the rotary stage. The impedance regulating part 140 has a base material 141 constituted of an insulating material, a first conduction part 143 electrically connected to the end part of the cylindrical substrate, a second conduction part 144 electrically connected to the rotary stage, and a connection part 142 for electrically connecting both conduction parts 143 and 144. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

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

  Conventionally, a deposited film for a semiconductor or the like made of an amorphous material (hereinafter, “amorphous” indicates non-single crystal) has been proposed, and some of them are put into practical use. ing. For example, amorphous silicon (hereinafter abbreviated as “a-Si”) compensated for at least one of hydrogen and halogen (for example, fluorine, chlorine, etc.) is used as the light receiving member. Such a light receiving member can be used as an element member in, for example, a semiconductor device, an electrophotographic photoreceptor device, an image input line sensor, an imaging device, a photovoltaic device, other various electronic elements, optical elements, and the like. it can.

  In forming this kind of deposited film, it is often required to make the deposited film uniform in film thickness and film characteristics. Therefore, it is effective to devise a method for supplying and exhausting the source gas, to rotate the substrate to be processed on which the deposited film is formed, and to adopt a method for making the plasma uniform when using the plasma CVD method. It is shown that there is.

  In addition, for the purpose of reducing the film thickness unevenness in the axial direction without increasing image defects, non-contact grounding means for grounding one end of the substrate by a rotating shaft for rotating the substrate and non-contacting the other end is provided. The provided apparatus is disclosed (refer patent document 1).

  In addition, an apparatus has been proposed in which the positioning of the upper and lower sides of the substrate and the conduction method when rotating the substrate are properly defined to make the deposited film uniform (see Patent Document 2).

A production system for continuously producing this kind of deposited film has also been proposed. In such a production system, the transport device before forming the deposited film and the transport means after forming the deposited film are separated to prevent dust and the like from adhering to the substrate before forming the deposited film. A series of deposited film forming apparatuses used has been proposed (see Patent Document 3).
Japanese Patent No. 3135031 Japanese Utility Model Publication No. 7-010934 Japanese Patent No. 2907404

  Conventionally, the deposited film has been made uniform and image defects have been reduced by the measures described above. However, in recent years, with the enhancement of the functions of such an apparatus using a deposited film, for example, the digitization and colorization of an electrophotographic apparatus, the uniformity of the deposited film and the reduction of image defects are required more than ever. . That is, for example, in a recent high-quality color apparatus using an electrophotographic process, since the gradation is improved, even with non-uniformity of deposited films and image defects, which had no problem in practical use, There is a possibility of causing visible unevenness in the formed image.

  In these respects, the conventional techniques as described above do not sufficiently consider both the uniformity of the deposited film and the reduction of image defects. That is, the uniformity of the deposited film, in particular the uniformity of the plasma treatment in the longitudinal direction of the substrate, the reduction of image defects, the reduction of adhesion of foreign matter to the substrate during the plasma treatment that causes image defects, and in addition to these Therefore, there is a need for a deposited film forming apparatus and a production system with good productivity.

  Specifically, for the uniformity of the plasma treatment in the longitudinal direction of the substrate, it is necessary to apply the discharge energy evenly. In order to reduce the adhesion of foreign matter to the substrate during plasma processing, it is necessary to reduce dust generation from the inside of the deposited film forming apparatus. In addition, a deposited film forming apparatus and a production system with good productivity must be compatible with an automatic substrate transfer system.

  The present invention has been made in view of the prior art as described above, and provides a deposited film forming apparatus that can form a deposited film with excellent film thickness and film property uniformity and with few image defects with high productivity. The purpose is to provide.

  In order to achieve the above object, a deposited film forming apparatus of the present invention comprises a reaction vessel capable of reducing the pressure inside, an exhaust means for evacuating the inside of the reaction vessel, and a cylindrical substrate. Substrate holder to be installed, holding means for rotatably holding the substrate holder, source gas introduction means for introducing source gas into the reaction vessel, and application means for applying discharge energy for exciting the source gas And both end portions of the cylindrical substrate are electrically connected to a reference grounding portion of the deposited film forming device and grounded, and at least one of the both end portions. Impedance adjusting means interposed between one end and the reference grounding portion is provided, and the impedance adjusting means is provided with a base material made of an insulating material and provided on the base material. A first conductive portion that is electrically connected to an end portion of the cylindrical substrate; a second conductive portion that is provided in the base material and is electrically connected to the reference grounding portion; the first conductive portion and the second conductive portion; And a connection portion that electrically connects the conduction portion.

  According to the present invention, it is possible to provide a deposited film forming apparatus capable of forming a deposited film with excellent uniformity in film thickness and film characteristics and few image defects with high productivity.

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

  FIG. 1 is a diagram schematically showing an example of a deposited film forming apparatus for manufacturing an electrophotographic photoreceptor by an RF (Radio Frequency) -CVD (Chemical Vapor Deposition) method.

  The deposited film forming apparatus 101 is an apparatus for forming a deposited film on the cylindrical substrate 102 by plasma processing, and includes a cathode electrode 103 constituting a side wall of a reaction vessel capable of reducing the pressure inside, and a cylindrical substrate 102 therein. And a substrate holder (substrate holding means) 107.

  The cylindrical board | substrate 102 should just have a material according to the intended purpose. As the material of the cylindrical substrate 102, 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. is there. Among these, aluminum is optimal in consideration of workability and manufacturing cost. In this case, as the aluminum forming the cylindrical substrate 102, it is preferable to use, for example, either an Al—Mg alloy or an Al—Mn alloy.

  A heater 111 is provided inside the substrate holder 107. Any heater 111 may be used as long as it can be used in vacuum. Specifically, electrical resistance heating elements such as sheath heaters, plate heaters, ceramic heaters and carbon heaters, heat radiation lamps such as halogen lamps and infrared lamps, and heat exchange means using liquid, gas, etc. as a heat medium Is the target. As the surface material of the heater 111, metals such as stainless steel, nickel, aluminum, and copper, ceramics, heat resistant polymer resins, and the like can be used.

  Further, in the deposited film forming apparatus 101, a source gas introduction pipe (source gas introducing means) 104 for introducing a source gas for forming a deposited film into the deposited film forming apparatus 101 is provided. The source gas introduction pipe 104 extends parallel to the longitudinal direction of the cylindrical substrate 102 held in the reaction vessel. The source gas introduction pipe 104 is connected to a gas supply system (not shown). The connection pipe includes a mixing 130 with a mass flow controller (not shown) for adjusting the flow rate of the source gas, and a source gas inflow valve for adjusting the flow rate of the source gas supplied to the source gas introduction pipe 104. 131 is provided.

  A high frequency power source (applying means) 133 is electrically connected to the side wall of the cylindrical cathode electrode 103 via a matching box 132 having a matching circuit. This side wall is insulated from the grounded bottom plate 108 and upper lid 109 of the deposited film forming apparatus 101 by an insulator 110 made of ceramics. The upper lid 109 is provided with a gate valve 134, from which a substrate holder 107 for holding the cylindrical substrate 102 is carried into, out of, and installed in the deposited film forming apparatus 101 by the substrate transfer mechanism 501 shown in FIG. The

  Further, a rotation support mechanism 115 that rotatably supports a substrate holder 107 that holds the cylindrical substrate 102 is provided below the deposited film forming apparatus 101. The rotation support mechanism 115 is configured to rotate the turntable 112 connected to the support shaft 113, the turntable 112 that supports the turntable 112, the turntable 112 on which the substrate holder 107 and the impedance adjustment unit 140 are placed. Motor 114. The support shaft 113 extends upward through the inside of the heater 111 and supports the substrate holder 107 via the support portion 116 at the upper portion thereof.

  Therefore, the cylindrical substrate 102 can be rotated around the support shaft 113 together with the turntable 112 while being mounted on the substrate holder 107. The turntable 112 of the rotation support mechanism 115 is electrically connected to the grounded bottom plate 108 and is in a grounded state.

  The upper end portion of the cylindrical substrate 102 is in contact with the cap 117, and the cap 117 is in contact with the substrate holder 107. Therefore, the upper end portion of the cylindrical substrate 102 is electrically connected to the turntable 112 via the cap 117, the substrate holder 107, the support portion 116, and the support shaft 113, and is grounded.

  The lower end portion of the cylindrical substrate 102 is in contact with the substrate holder 107, and the substrate holder 107 is in contact with the turntable 112 of the rotation support mechanism 115 through the impedance adjustment unit 140. Therefore, the lower end portion of the cylindrical substrate 102 is grounded via the impedance adjustment unit 140 and the turntable 112 of the rotation support mechanism 115.

  A vacuum pump unit 120 serving as an exhaust means is connected to an exhaust port 118 of the bottom plate 108 via an exhaust pipe 121. An exhaust main valve 119 is provided in the exhaust pipe 121. A vacuum gauge 122 for measuring pressure is attached to the exhaust pipe 121. By using these, the inside of the deposited film forming apparatus 101 can be maintained at a predetermined pressure suitable for each process. As the vacuum pump unit 120, for example, a rotary pump, a mechanical booster pump, or the like can be used.

  Next, the impedance adjustment unit 140 will be described with reference to FIG.

  FIG. 2 is a diagram schematically showing the impedance adjusting unit shown in FIG. FIG. 2A is a top view thereof, and FIG. 2B is a side view seen from the direction of the arrow in FIG.

  The impedance adjustment unit 140 includes a base body 141, a first conduction unit 143, a second conduction unit 144, and a connection unit 142 that connects these conduction units.

  The base body 141 uses an insulating material as a base material. As the insulating material, for example, resins such as polytetrafluoroethylene and polycarbonate, and glasses such as quartz glass and pyrex glass can be used. In addition to these, ceramic materials such as alumina, zirconia, mullite, cordierite, silicon carbide, boron nitride, and aluminum nitride can be used as the insulating material, and a mixture thereof can also be used.

  The first conducting portion 143 is a portion that conducts with one end of the cylindrical substrate 102. In the case of the configuration shown in FIG. 1, the first conductive portion 143 is electrically connected to the lower end portion of the cylindrical substrate 102 via the substrate holder 107.

  The second conducting portion 144 is a portion that conducts with the reference grounding portion. In the case of the configuration shown in FIG. 1, as described above, the upper end portion of the cylindrical substrate 102 is grounded via the cap 117, the substrate holder 107, the support portion 116, and the support shaft 113. On the other hand, the lower end portion of the cylindrical substrate 102 is grounded via the substrate holder 107, the turntable 112 and the support shaft 113. The turntable 112 and the support shaft 113 are electrically connected to each other, and the turntable 112 forms a reference grounding portion common to both the upper end portion and the lower end portion of the cylindrical substrate 102. The second conducting part 144 is thus conducted to the turntable 112.

  The material of the first and second conducting portions 143 and 144 may be any material as long as it has conductivity, and examples thereof include aluminum and stainless steel. Moreover, there is no restriction | limiting in particular as long as those shapes also conduct | electrically_connect, A leaf | plate spring shape or a convex shape may be sufficient as shown in FIG. Moreover, there is no restriction | limiting in particular also in those installation places, as shown in FIG. 2, you may provide in one place or in multiple places.

  The connection part 142 connects the first conduction part 143 and the second conduction part 144. As a material of the connection part 142, what is necessary is just to have electroconductivity, and aluminum, stainless steel, etc. are mentioned. Furthermore, the installation location of the connecting portion 142 is not particularly limited, and may be provided on the outer peripheral surface of the mother body 141 as shown in FIG.

  FIG. 3 is a diagram schematically showing another form of the impedance adjustment unit. FIG. 3A is a top view thereof, and FIG. 3B is a cross-sectional view taken along the line ZZ in FIG. In the configuration shown in FIG. 3, the connection portion 142 is provided on the inner peripheral surface of the mother body 141.

  A film is deposited on the outer peripheral surface of the impedance adjusting unit 140 during the film forming process. Therefore, when the connection part 142 is provided on the outer peripheral surface of the impedance adjustment part 140, a film is deposited on the connection part 142. When a film is deposited on the connecting portion 142, the impedance of the connecting portion 142 changes. Therefore, when the impedance adjusting unit 140 is repeatedly used, the continuity of the connecting portion 142 may gradually change. On the other hand, as shown in FIG. 3, by providing the connecting portion 142 on the inner peripheral surface of the mother body 141, the connecting portion 142 is placed at a position separated from the internal space of the reaction vessel, which is a space for exciting the source gas. Can be arranged. Thereby, since a film is prevented from being deposited on the connection part 142, reproducibility when the impedance adjustment part 140 is repeatedly used is improved.

  FIG. 4 is a diagram schematically showing still another form of the impedance adjustment unit. 4A is a top view thereof, and FIG. 4B is a cross-sectional view taken along the line ZZ in FIG. 4A. In the configuration shown in FIG. 4, the connection portion 142 is provided inside the mother body 141.

  As shown in FIG. 4, by providing the connection portion 142 inside the base body 141, it is possible to prevent a film from being deposited on the connection portion 142 as in the configuration shown in FIG. 3.

  In the case where the connecting portion 142 is provided on the surface of the mother body 141 and is exposed, the connecting portion 142 made of metal is corroded by an etching gas used for cleaning the film deposited on the inner wall of the reaction vessel. May be. However, as shown in FIG. 4, by providing the connecting portion 142 inside the base body 141, the connecting portion 142 is disposed at a position separated from the internal space of the reaction vessel, which is a space for exciting the source gas. Become. Therefore, the possibility that the connecting portion 142 is exposed to the etching gas is greatly reduced.

  As described above, when the connection portion 142 is provided inside the base body 141 as shown in FIG. 4, no film is deposited on the connection portion 142, and the connection portion 142 is not corroded. Therefore, reproducibility when the impedance adjusting unit 140 is repeatedly used is improved, and the stability of the deposited film formation can be greatly improved.

  Further, by changing the impedance between the first conducting portion 143 and the second conducting portion 144 by the connecting portion 142, the impedance between the lower end portion of the cylindrical substrate 102 and the turntable 112 serving as the reference grounding portion. Can be adjusted. 2 and 3, the impedance is adjusted by changing the inductance component by changing the length of the connecting portion 142. Further, in the configuration shown in FIG. 4, the impedance is adjusted by changing the inductance component by making the connecting portion 142 into a coil shape.

  The adjustment of the impedance is performed so that the impedance from the plurality of end portions of the cylindrical substrate to the reference grounding portion of the deposited film forming apparatus becomes equal. In the configuration shown in FIG. 1, the impedance from each of the upper end portion and the lower end portion of the cylindrical substrate 102 to the turntable 112 serving as the reference grounding portion is adjusted to be equal. The impedance is expressed as Z = R + jωL. Here, R is a skin resistance component, L is an inductance component, j is an imaginary unit, and ω is a high-frequency angular frequency.

  The skin resistance component R changes depending on the material in the electrical path from the end of the cylindrical substrate to the reference grounding portion. However, in the case of a nonmagnetic material, for example, aluminum (Al), the resistance value with respect to a high frequency of 10 [MHz] is about 1.03E−2 [Ω / m]. In addition, in stainless steel (SUS304), the resistance value with respect to a high frequency of 10 [MHz] is about 5.33E-2 [Ω / m]. Therefore, when the electrical path to the reference grounding portion is made of a nonmagnetic material such as Al or SUS304, the impedance Z for the high frequency applied thereto is substantially determined by the inductance component. Further, the inductance component changes depending on the distance to the reference grounding portion.

  As described above, the upper end portion of the cylindrical substrate 102 is electrically connected to the turntable 112 serving as a reference ground portion via the cap 117, the substrate holder 107, the support portion 116, and the support shaft 113. The lower end portion of the cylindrical substrate 102 is electrically connected to the turntable 112 serving as a reference grounding portion via the substrate holder 107 and the impedance adjusting unit 140. Therefore, when comparing the distance from each end to the reference grounding portion, the linear distance to the reference grounding portion is longer at the upper end of the cylindrical substrate 102, and as a result, the upper end of the cylindrical substrate 102 is increased. The inductance component of the electrical path from the reference ground to the reference grounding portion increases. Therefore, the impedance adjustment unit 140 adjusts the inductance component so that the upper end portion and the lower end portion of the cylindrical substrate 102 are substantially equal. For example, the impedance from the upper end portion of the cylindrical substrate 102 to the reference ground portion is 100. At this time, by adjusting the impedance from the lower end portion of the cylindrical substrate 102 to the reference ground portion by the impedance adjusting unit 140 to about 90 to 110, both impedances can be made substantially equal.

  Next, the substrate transport mechanism 501 will be described with reference to FIG.

  FIG. 5 is a diagram schematically showing the substrate transport mechanism. The substrate transfer mechanism 501 includes a transfer container 502 that can be vacuum-tight and has a vertical mechanism for docking with the deposited film forming apparatus 101. A gate valve 505 is provided below the transfer container 502, and an arm 503 having a holding portion 504 that holds the substrate holder 107 and capable of moving up and down is provided inside the transfer container 502. The transfer container 502 can move in the horizontal direction along the rail 506. By this substrate transport mechanism 501, the substrate holder 107 on which the cylindrical substrate 102 is mounted can be carried into, set in, and carried out from the deposited film forming apparatus 101 while maintaining the deposited film forming apparatus 101 in a vacuum state. As a result, not only the productivity is improved, but also contamination inside the deposited film forming apparatus 101 can be prevented, which is effective in reducing image defects.

  An example of a procedure for forming a deposited film using the deposited film forming apparatus 101 configured as described above will be described below with reference to FIG.

  First, the substrate holder 107 on which the cylindrical substrate 102 is mounted is loaded and installed in the deposited film forming apparatus 101 by the substrate transport mechanism 501, and the deposited film forming apparatus 101 is evacuated by a vacuum pump unit (not shown). Subsequently, a gas such as Ar or He necessary for heating the cylindrical substrate 102 is introduced into the deposited film forming apparatus 101 via the mixing 130, the source gas inflow valve 131, and the source gas introduction pipe 104. Then, using a vacuum pump unit (not shown) and an exhaust main valve 119, adjustment is performed while looking at the vacuum gauge 122 so that the inside of the deposited film forming apparatus 101 becomes a predetermined pressure. Next, after the predetermined pressure is reached, the temperature of the cylindrical substrate 102 is set to a desired value of about 200 [° C.] to 450 [° C.], more preferably about 250 [° C.] to 350 [° C.] by the heater 111. Control to temperature.

  After the preparation for forming the deposited film is completed by the above procedure, a photoconductive layer is formed on the cylindrical substrate 102.

  For this purpose, first, a heating gas and a raw material gas for forming a deposited film are mixed and introduced via a mixing 130, and the introduced gas is adjusted to have a desired flow rate. At that time, the vacuum pump unit 120 and the exhaust main valve 119 are adjusted while checking the vacuum gauge 122 so that the inside of the cylindrical reaction vessel 103 has a desired pressure of about 13.3 [mPa] to 1330 [Pa]. . This adjustment can be performed, for example, by adjusting the rotation frequency of a mechanical booster pump of a vacuum pump unit (not shown).

As a source gas used for forming a deposited film, amorphous silicon such as silane (SiH ₄ ), disilane (Si ₂ H ₆ ), silicon tetrafluoride (SiF ₄ ), and disilicon hexafluoride (Si ₂ F ₆ ) is formed. Raw material gas or a mixed gas thereof can be used. As the dilution gas, hydrogen (H ₂ ), argon (Ar), helium (He), or the like can be used. Further, as a characteristic improving gas for changing the band gap width of the deposited film, a gas containing nitrogen atoms, a gas containing oxygen atoms, a hydrocarbon, a fluorine compound, or a mixed gas thereof may be used in combination. Examples of the gas containing nitrogen atoms used at this time include nitrogen (N ₂ ) and ammonia (NH ₃ ). Examples of the gas containing oxygen atoms include oxygen (O ₂ ), nitrogen monoxide (NO), nitrogen dioxide (NO ₂ ), dinitrogen monoxide (N ₂ O), carbon monoxide (CO), carbon dioxide (CO ₂ ) And the like. Examples of the hydrocarbon include methane (CH ₄ ), ethane (C ₂ H ₆ ), ethylene (C ₂ H ₄ ), acetylene (C ₂ H ₂ ), propane (C ₃ H ₈ ) and the like. Examples of the fluorine compound include germanium tetrafluoride (GeF ₄ ) and nitrogen fluoride (NF ₃ ). Further, for the purpose of doping treatment, a dopant gas such as diborane (B ₂ H ₆ ), boron fluoride (BF ₃ ), or phosphine (PH ₃ ) may be simultaneously introduced into the discharge space.

  Next, after the pressure in the deposited film forming apparatus 101 is stabilized, the high-frequency power supply 133 is set to a desired power, and the high-frequency power is supplied to the cathode electrode 103 via the high-frequency matching box 132, whereby high-frequency glow discharge is performed. Wake up. The supplied power can be, for example, an RF band of about 13.56 [MHz] to 45 [MHz], particularly a frequency of 13.56 [MHz]. By this discharge energy, the source gas introduced into the deposited film forming apparatus 101 is excited to generate excited species, that is, decomposed, and a deposited film mainly containing desired silicon atoms is formed on the cylindrical substrate 102. It is formed.

  In order to form a uniform deposited film, the cylindrical substrate 102 is rotated at the same time as the deposited film is formed or from the stage where the cylindrical substrate 102 is heated. This rotation is about 1 [rpm] to 10 [rpm], for example, 1 [rpm]. By doing so, a uniform deposited film is formed in the circumferential direction of the cylindrical substrate 102.

  As described above, a deposited film is formed on the outer peripheral surface of the cylindrical substrate 102.

After the deposited film is formed, the supply of the source gas and the high frequency power is stopped and the inside of the deposited film forming apparatus 101 is exhausted. Thereafter, the inside of the deposited film forming apparatus 101 and the source gas introduction pipe 104 is purged using a purge gas, for example, at least one of an inert gas such as Ar and N ₂ . After the completion of the purge process, the substrate transfer mechanism 501 is used to take out the substrate holder 107 on which the cylindrical substrate 102 is mounted from the deposited film forming apparatus 101.

  Thereafter, the powdery by-product deposited in the deposited film forming apparatus 101 is cleaned as necessary. As a procedure at that time, first, instead of the cylindrical substrate 102, a cleaning dummy substrate (not shown) having the same shape as this is placed in the deposited film forming apparatus 101 using the substrate transfer mechanism 501, and vacuum The inside of the deposited film forming apparatus 101 is exhausted by the pump unit 120. Subsequently, a cleaning gas necessary for the cleaning process is introduced into the deposited film forming apparatus 101 via the mixing 130 and the source gas introduction pipe 104. Then, using the vacuum pump unit 120 and the exhaust main valve 119, adjustment is performed while looking at the vacuum gauge 122 so that the inside of the deposited film forming apparatus 101 becomes a predetermined pressure.

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. Use ClF ₃ which is effective. In the present embodiment, it is effective to use an inert gas for dilution in order to adjust the concentration of the cleaning gas. Examples of the inert gas include He, Ne, and Ar. Among them, it is preferable to use Ar.

  After the pressure in the deposited film forming apparatus 101 is stabilized, the high frequency power supply 133 is set to a desired power, and the high frequency power is supplied to the cathode electrode 103 via the high frequency matching box 132, thereby generating a high frequency glow discharge. . The supplied power can be, for example, an RF band of about 13.56 [MHz] to 45 [MHz], particularly a frequency of 13.56 [MHz]. By this discharge energy, the cleaning source gas introduced into the deposited film forming apparatus 101 is decomposed, and the inside of the deposited film forming apparatus 101 is cleaned.

Next, the supply of high frequency power is stopped after the cleaning process, and the deposited film forming apparatus 101 is evacuated. Thereafter, the inside of the deposited film forming apparatus 101 and the source gas introduction pipe 104 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, a dummy substrate for cleaning (not shown) is taken out from the deposited film forming apparatus 101 using the substrate transport mechanism 501.

  In the deposited film forming apparatus of the present embodiment, the reference grounding portion of the deposited film forming apparatus 101 from each of the lower end portion that is one end portion and the upper end portion that is the other end portion of both ends of the cylindrical substrate 102. The impedance adjustment unit 140 adjusts the impedance of the electrical path up to. Thereby, the electrical state in the longitudinal direction of the cylindrical substrate 102 becomes equal. As a result, the discharge energy is applied uniformly, and the uniformity of the plasma processing can be improved.

  Furthermore, as a result of improving the uniformity of the plasma, the uniformity of the deposited film deposited on the structure other than the cylindrical substrate 102 is also improved. Therefore, since the stress generated in such a deposited film is reduced, the adhesion of the deposited film to a structure other than the cylindrical substrate 102 is improved, and the film is peeled off during the formation of the deposited film. The possibility of dust generation is reduced. As a result, it is possible to reduce the possibility of image defects occurring due to dust generation.

  Further, the improvement of the uniformity of the volume film as described above can be performed by the impedance adjustment unit 140 having a simple configuration, and the substrate transport mechanism 501 is provided in the substrate holder 107 so as to automatically transport the substrate holder 107. There is no effect on the structure of the holding part. Therefore, the deposited film forming apparatus 101 according to the present embodiment is excellent in productivity because the substrate holder 107 holding the cylindrical substrate 102 can be automatically transported (loaded / installed / unloaded) by the substrate transport mechanism 501.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited at all by these. In the following description, the same components as those shown in the above-described embodiments will be described using the same reference numerals.

Example 1
A deposited film forming apparatus 101 shown in FIG. 1 is used to form amorphous silicon having a layer structure shown in FIG. 8 on a cylindrical substrate 102 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 deposited film (hereinafter abbreviated as an electrophotographic photosensitive member) was formed. A substrate transport mechanism 501 shown in FIG. 5 was used for transporting the substrate holder 107 on which the cylindrical substrate 102 was mounted.

  In FIG. 8, reference numeral 801 denotes a component of the cylindrical substrate 102, reference numeral 802 denotes a lower blocking layer (first layer), reference numeral 803 denotes a first photoconductive layer (second layer), and reference numeral 804 denotes A second photoconductive layer (third layer), reference numeral 805 denotes a surface layer (fourth layer).

  In the present embodiment, as the impedance adjustment unit 140, the one shown in FIG. 4 is used. For the base 141, alumina ceramics, which is an insulating material, was used. Stainless steel was used as the material of the first and second conducting parts 143 and 144, and these were made into a leaf spring shape. As the connection part 142, as shown in FIG. 4, a stainless steel wire wound around a cylindrical alumina ceramic in a coil shape was used. The connection part 142 is provided inside the impedance adjustment part 140 configured by the base material 141.

  With respect to the produced electrophotographic photosensitive member, “Vd longitudinal direction unevenness”, “Vh longitudinal direction unevenness”, and “white spot” were evaluated as follows. In addition, “productivity” and “reproducibility” were also evaluated.

Evaluation of “Vd Longitudinal Unevenness” and “Vh Longitudinal Unevenness” For these evaluations of electrophotographic photosensitive member characteristics, a copier (an iR5000 modified machine manufactured by Canon Inc.) was used. FIG. 9 shows a schematic diagram of the copying machine. In FIG. 9, an electrophotographic photosensitive member 901 is supported so as to be rotatable in the clockwise direction in the figure. Around the electrophotographic photosensitive member 901, a pre-exposure device 908 for forming an electrostatic latent image, a main charger 902, a latent image forming exposure device 909, and a potential sensor 903 are sequentially arranged in the clockwise direction. ing. Further, a developing device 904 for performing development by attaching toner on the electrostatic latent image, a transfer charging device 905a for transferring the toner image to a recording medium, and a separation charging device 905b are arranged. Further, a cleaner 910 having a cleaning roller 906 and a cleaning blade 907 for removing residual toner is disposed.

  When measuring the electrophotographic photosensitive member characteristics, the developing device 904 and the cleaner 910 are removed. Then, instead of the developing unit 904, a potential probe (Model 344, not shown) that can measure the electrophotographic characteristics at a predetermined position in the longitudinal direction of the electrophotographic photosensitive member is attached, and the electrophotographic characteristics of the electrophotographic photosensitive member are adjusted. taking measurement. The electrophotographic characteristics thus measured were evaluated according to the following criteria.

"Vd longitudinal unevenness"
The process speed is 265 mm / sec, the amount of light for pre-exposure (LED with a wavelength of 680 nm) is 4 lx · s, and the surface potential at the center position in the longitudinal direction of the electrophotographic photosensitive member is 450 V (dark potential) as measured by the potential probe. The current value of the main charger 902 is adjusted. Thereafter, the potential probe is moved in the longitudinal direction from the end of the electrophotographic photosensitive member, and measurement is performed at 9 points at intervals of 40 mm in the longitudinal direction, and the difference between the maximum value and the minimum value at the 9 points is calculated as Vd. The longitudinal unevenness was evaluated. Evaluation was carried out by relative evaluation with the result obtained in Comparative Example 1 as 100. In other words, the smaller the number, the better the evaluation result.

"Vh longitudinal unevenness"
The current value of the main charger 902 was adjusted so that the surface potential at the center position in the longitudinal direction of the electrophotographic photosensitive member was 450 V (dark potential) by the same procedure as the Vd longitudinal unevenness. Thereafter, image exposure (laser with a wavelength of 660 nm) was irradiated to adjust the light quantity of the image exposure light source so that the surface potential at the middle position measured with the potential probe was 200 V (bright potential). Thereafter, the potential probe is moved in the longitudinal direction from the end of the electrophotographic photosensitive member, and measurement is performed at 9 points at intervals of 40 mm in the longitudinal direction, and the difference between the maximum value and the minimum value at the 9 points is calculated as Vh. The longitudinal unevenness was evaluated. Evaluation was carried out by relative evaluation with the result obtained in Comparative Example 1 as 100. In other words, the smaller the number, the better the evaluation result.

Evaluation of “White Pochi” Using a Canon iR5000 copying machine, an image obtained by copying an entire black A3 size original was observed, and the diameter of the electrophotographic photosensitive member per circle was 0. The number of white spots (portions where no image was formed) of 10 mm or more was counted. Evaluation was carried out by relative evaluation when the result obtained in Comparative Example 2 was taken as 100. In other words, the smaller the number, the better the evaluation result.

Evaluation of “stability” The fluctuation width of the Vd bus line unevenness when 20 cycles of the electrophotographic photosensitive member were continuously produced was evaluated. That is, the difference between the maximum value and the minimum value of the Vd bus line unevenness of the electrophotographic photosensitive member obtained in each cycle was evaluated as stability.

  Evaluation was carried out by relative evaluation when the result obtained in Comparative Example 2 was taken as 100. In other words, the smaller the number, the better the evaluation result.

Evaluation of “Productivity” The time required for a series of steps when producing 20 cycles of electrophotographic photoreceptors continuously, that is, production tact, was compared. Evaluation was carried out by relative evaluation when the result obtained in Comparative Example 2 was taken as 100. In other words, the smaller the number, the better the evaluation result.

Ranking of each evaluation result Each evaluation result was ranked according to the following criteria.
◎ ・ ・ ・ less than 80 ○ ・ ・ ・ 80 or more and less than 90 Δ ・ ・ ・ 90 or more and 100 or less × ... greater than 100 Overall evaluation 5 items above (“Vd longitudinal unevenness” “Vh longitudinal unevenness” “White potty” "Productivity" and "Stability") were evaluated based on the following criteria.
◎ ・ ・ ・ All items ◎
○ ・ ・ ・ ◎ or ○ for each item
Δ: One or more Δ for each item, ×: No ×: One or more for each item ×: The results of each evaluation and comprehensive evaluation are shown in Table 2.

(Example 2)
In contrast to Example 1, the impedance adjusting unit 140 was changed to the form shown in FIG. 3 to produce an electrophotographic photosensitive member, and the same evaluation as in Example 1 was performed.

  Alumina ceramics was used as the material of the base 141. Moreover, stainless steel was used as the material of the first and second conducting portions 143 and 144, and these were formed into a leaf spring shape. As the connection part 142, a stainless steel wire pasted on the inner peripheral surface of the mother body 141 was used. Thereby, the connection part 142 is separated from the internal space of the reaction vessel which is a space for exciting the source gas.

  The evaluation results are shown in Table 2.

(Example 3)
In contrast to Example 1, the impedance adjustment unit 140 was changed to the form shown in FIG. 2 to produce an electrophotographic photosensitive member, and the same evaluation as in Example 1 was performed.

  Alumina ceramics was used as the material of the base 141. Further, as the material of the first and second conducting portions 143 and 144, stainless steel was used and a leaf spring shape was formed. As the connection part 142, a stainless steel wire pasted on the outer peripheral surface of the base body 141 was used.

  The evaluation results are shown in Table 2.

[Comparative Example 1]
An electrophotographic photosensitive member was produced on a cylindrical substrate 602 made of aluminum having a diameter of 80 mm, a length of 358 mm, and a thickness of 3 mm using the deposited film forming apparatus 601 shown in FIG. went. A substrate transport mechanism 501 shown in FIG. 5 was used for transporting the substrate holder 607 on which the cylindrical substrate 602 was mounted. The evaluation results are shown in Table 2.

  The deposited film forming apparatus 601 used in this comparative example is different from the deposited film forming apparatus 101 of the embodiment shown in FIG. 1 in that the impedance adjusting unit 140 is not provided. That is, the impedance from the upper end portion of the cylindrical substrate 602 to the ground is greatly different from the impedance from the lower end portion of the cylindrical substrate 602 to the ground. In addition, since the holding part by the board | substrate conveyance mechanism 501 is provided in the upper part of the board | substrate holder 607, the board | substrate holder 607 can respond to automatic conveyance.

[Comparative Example 2]
An electrophotographic photosensitive member was produced using the deposited film forming apparatus 701 shown in FIG. 7, and the same evaluation as in Example 1 was performed. The evaluation results are shown in Table 2.

  The upper structure of the substrate holder 707 of this comparative example will be described. At the upper part of the substrate holder 707, there is a sliding portion 762 inside the cylindrical body 761, and a support shaft 760 fixed to the top plate 709 is inserted into the cylindrical body 761 to come into contact with the sliding portion 762 and slide. The upper part of the substrate holder 707 is electrically grounded and supported rotatably. In this comparative example, a plurality of metal leaf springs were used for the sliding portion 762.

  The deposited film forming apparatus 701 used in this comparative example is in a state where the upper and lower ends of the cylindrical substrate 702 are electrically grounded at substantially the same distance as the deposited film forming apparatus 101 of the embodiment shown in FIG. ing. However, it differs from the deposited film forming apparatus 101 shown in FIG. 1 in that it cannot support automatic conveyance by the substrate conveyance mechanism. Therefore, in this comparative example, the substrate holder 707 on which the cylindrical substrate 702 was mounted was transported manually.

  As can be seen from Table 2, with respect to each longitudinal unevenness, the longitudinal unevenness was improved by making the upper and lower sides of the substrate holder grounded in a direct current state (comparing to Comparative Example 1, Examples 1 to 3 and Comparative Example 1). Example 2). Furthermore, the longitudinal direction unevenness was further improved by using the impedance adjusting unit (Examples 1 to 3 as compared to Comparative Example 2). The reason is presumed as follows.

  A cylindrical substrate having a certain distance in the longitudinal direction has a difference in impedance component between the central portion and the end portion of the cylindrical substrate, particularly an inductance component due to a difference in distance to the ground surface. Therefore, there are cases where the difference in inductance component cannot be ignored simply by grounding both ends of the cylindrical substrate. In each embodiment, a certain amount of inductance component is given to one end portion of the cylindrical substrate by the impedance adjusting unit, and the impedance from each end portion of the cylindrical substrate is made equal. By doing so, the difference in the inductance component between the central portion and the end portion of the cylindrical substrate can be made relatively small in view of the overall impedance, so it is considered that the longitudinal unevenness is further improved.

  Regarding the white spot, in Comparative Example 2, a sliding part was provided in the reaction space above the substrate holder, and thus a white spot that was thought to be caused by dust generation from the sliding part was recognized. In Examples 1 to 3, the evaluation of white spots is better than that of Comparative Example 1. This is presumably because Examples 1 to 3 improved the uniformity of the deposited film on the cylindrical substrate, but also improved the uniformity of the deposited film deposited on other than the cylindrical substrate. As a result, the strain such as internal stress in the deposited film, which has occurred in the past, is reduced and the adhesion of the deposited film is improved, and the film peeling of the deposited film other than the cylindrical substrate during the formation of the deposited film is reduced. Therefore, it is presumed that the evaluation of the white spot was improved.

  Regarding productivity, Comparative Example 2 does not correspond to automatic conveyance by the substrate conveyance mechanism, but Examples 1 to 3 and Comparative Example 1 correspond to automatic conveyance. When automatic conveyance is not possible, that is, when the work is done manually, the time required for a series of processes for producing an electrophotographic photosensitive member is about twice as long as when automatic conveyance can be used, even if the deposition film formation time is the same. there were. The reason is that it is necessary to sufficiently perform a purging step after the formation of the deposited film and after the cleaning process, a waiting time until the cylindrical substrate, the substrate holder and the dummy substrate are sufficiently cooled, and the deposited film formation. This is due to the need for work to increase the cleanliness of the reaction vessel before. It should be noted that in Examples 1 to 3 and Comparative Example 1 using automatic conveyance are superior to Comparative Example 2 in which manual conveyance is performed, the white spot evaluation is superior, and it is understood that automatic conveyance is also effective in reducing image defects. .

  Regarding stability, in Comparative Example 2, since the sliding portion is in the reaction space, it is estimated that the stability of the energized state of the sliding portion may not be sufficient during the formation of the deposited film. Specifically, it is conceivable that the adhesion to the support shaft deteriorates due to a decrease in the elasticity of the metal leaf spring at high temperature and in a plasma environment, and the influence of adhesion of the deposited film. Examples 1 to 3 and Comparative Example 1 are considered to be excellent in terms of stability because the sliding part is not arranged in the reaction space as in Comparative Example 2. Moreover, compared with Example 3, the result of Example 2 is somewhat superior in stability. The reason is presumed as follows. In Example 2, since the connection part 142 is separated from the space for exciting the source gas, it is considered that damage caused by the excited deposition film forming gas and the cleaning processing gas is reduced. Furthermore, compared with Example 2, the result of Example 1 is superior in stability. In the first embodiment, since the connection portion 142 is provided inside the impedance adjustment portion using an insulating material as a base material, damage due to the deposition film forming gas and the cleaning processing gas does not substantially occur. Therefore, it is considered that it is possible to form a deposited film with good uniformity even when used for a long period of time.

  Summing up the above, each embodiment of the present invention is compatible with evaluation of each longitudinal unevenness and white spot, and also has good productivity. That is, it can be seen that an electrophotographic photosensitive member having a uniform deposited film, few image defects, and high productivity can be produced.

It is a figure showing typically the deposited film formation device concerning one embodiment of the present invention. It is a schematic diagram which shows the structure of the impedance adjustment part in the deposited film formation apparatus shown in FIG. It is a schematic diagram which shows the other structure of the impedance adjustment part in the deposited film formation apparatus shown in FIG. It is a schematic diagram which shows the further another structure of the impedance adjustment part in the deposited film formation apparatus shown in FIG. It is a figure which shows typically the structure of the base | substrate conveyance mechanism in the deposited film formation apparatus shown in FIG. It is a figure which shows typically the deposited film forming apparatus which concerns on the comparative example 1. FIG. It is a figure which shows typically the deposited film forming apparatus which concerns on the comparative example 2. FIG. It is a schematic diagram showing a layer structure of an amorphous silicon electrophotographic photoreceptor. 1 is a diagram showing a schematic configuration of a copying machine used for evaluating electrophotographic photosensitive member characteristics. FIG.

Explanation of symbols

101 Deposited film forming apparatus 102 Cylindrical substrate 103 Cathode electrode (reaction vessel)
104 Source gas introduction pipe (source gas introduction means)
107 Substrate holder 115 Rotation support mechanism (holding means)
133 High frequency power supply (applying means)
140 Impedance adjustment unit 141 Mother body 142 Connection unit 143 First conduction unit 144 Second conduction unit

Claims (5)

A reaction vessel capable of depressurizing the inside, an exhaust means for exhausting the inside of the reaction vessel, a cylindrical substrate, a substrate holder installed in the reaction vessel, and a substrate holder rotatably held In a deposited film forming apparatus comprising: a holding unit; a source gas introduction unit that introduces a source gas into the reaction vessel; and an application unit that applies discharge energy that excites the source gas.
Both ends of the cylindrical substrate are configured to be electrically connected and grounded to the reference grounding portion of the deposited film forming apparatus, respectively, and at least one end of the both ends, the reference grounding portion, Impedance adjustment means interposed between
The impedance adjusting means includes a base material made of an insulating material, a first conductive portion provided on the base material and conducted to an end of the cylindrical substrate, and the reference ground provided on the base material. A deposited film forming apparatus, comprising: a second conduction portion that is electrically connected to a portion; and a connection portion that electrically connects the first conduction portion and the second conduction portion.   The deposited film forming apparatus according to claim 1, wherein the connection portion is disposed at a position separated from an internal space of the reaction vessel.   The deposited film forming apparatus according to claim 2, wherein the connection portion is provided inside the base material.   The impedance of the electrical path between one end of the cylindrical substrate and the reference grounding portion, and the impedance of the electrical path between the other end of the cylindrical substrate and the reference grounding portion The deposited film forming apparatus according to claim 1, wherein the deposited film forming apparatus is adjusted by the impedance adjusting means so as to be substantially equal.   5. The deposited film forming apparatus according to claim 1, wherein the holding unit includes a turntable, and the reference grounding unit is configured by the turntable.

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