JP2001335942A - Method for depositing film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for depositing a film, in which occurrence of film defects as well as partial fluctuations in film qualities can be suppressed and a high quality deposited film having superior uniformity can be produced with stable and high reproducibility. SOLUTION: In this method for forming a deposit film, a substrate-preheating step for producing plasma and hating the substrate by introducing substrate- heating gas and high-frequency power is provided in forming the deposit film on the substrate under reduced pressure in a reaction vessel. In a subsequent gas-replacing step, while heating substrate by plasma in a state where the high- frequency electric power is continuously introduced, the flow rate of the substrate-heating gas is gradually decreased and the flow rate of source gas for deposit film formation is gradually increased to replace the substrate-heating gas with the source gas for deposit film formation, followed by the deposit film forming operation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for forming a deposited film on a substrate. In particular, the present invention relates to a method for forming a functional deposited film on a substrate, for example, an amorphous semiconductor film used for a semiconductor device, a light receiving member for electrophotography, a line sensor for image input, an imaging device, a photovoltaic device, and the like. Specifically, the present invention relates to a method for forming a deposited film capable of improving the uniformity and reproducibility of the film characteristics of a functional deposited film such as the above-described amorphous semiconductor film.

[0002]

2. Description of the Related Art Conventionally, as a device member used for a semiconductor device, an electrophotographic photoreceptor, an image input line sensor, an image pickup device, a photovoltaic device, other various electronic elements, an optical element, etc., an amorphous deposit is used. A film, for example, amorphous silicon, especially amorphous silicon (hereinafter abbreviated as a-Si (H, X)) compensated with hydrogen and / or halogen (for example, fluorine, chlorine, etc.), or crystalline silicon It has been proposed to use deposited films, such as diamond films, some of which have been put to practical use. On the other hand, the development of the above-described various methods for forming a functional deposited film has also been advanced, and specifically,
The development of a plasma CVD method, that is, a method of decomposing a raw material gas by direct current, high frequency, or microwave glow discharge to form a deposited film on a substrate such as glass, quartz, a heat-resistant synthetic resin film, stainless steel, or aluminum. It is being advanced and put into practical use.

In particular, when forming a deposited film having a large area such as a photoreceptor for electrophotography, a technique capable of forming a uniform and high-quality deposited film, and for improving reproducibility and productivity. A lot of research has been directed at this technology, and various proposals have been made.

For example, according to Japanese Patent Application Laid-Open No. 1-298173, high-quality deposition is achieved by heating a substrate by the thermal energy of plasma and controlling the temperature of the substrate by flowing a cooling gas from inside the substrate. A method for making a membrane is disclosed, the method being reproducible,
It is described as a technique that enables production of a deposited film with high productivity. On the other hand, according to JP-A-6-242624,
In the plasma CVD method, a frequency of 50 to 450 MHz
A technique for improving the film quality by using high-frequency power is disclosed. As described above, in a method of manufacturing a deposited film using a high-frequency plasma CVD method (hereinafter, abbreviated as PCVD), an improved technique is accumulated with respect to a method and conditions for improving the film quality of the obtained deposited film. .

[0005] For example, FIG. 1 shows an example of an apparatus which utilizes the above-mentioned conventionally accumulated improvement techniques and is used for producing a photoconductor for electrophotography. FIG. 1 shows a-S by PCVD.
FIG. 1 is a schematic configuration diagram of an apparatus for forming i (H, X) and the like, and particularly shows the configuration of an apparatus for forming a deposited film on a cylindrical substrate suitable for an electrophotographic photosensitive member. P shown in FIG.
The configuration of the deposition film forming apparatus using the CVD method is as follows.

This apparatus is roughly divided into three types of apparatus parts, a deposition apparatus 1100 and a source gas supply apparatus 12.
00, an exhaust device 1300 for reducing the pressure inside the reaction vessel 1111. A cylindrical substrate 1112 mounted on a substrate holder 1113, a substrate cooling means 1114, a gas introduction pipe 1115, and a cathode electrode 1116 are provided in a reaction vessel 1111 in the deposition apparatus 1100.
Further, a high-frequency matching box 1118 and a high-frequency power supply 1117 are connected to the cathode electrode 1116. The base holder 1113 is connected to the rotation mechanism 1122, and is rotated by the rotation drive unit 1120. The cylindrical base 1112 is configured to be mounted on the base holder 1113 so as to maintain airtightness with respect to the reaction vessel 1111. The substrate cooling unit 1114 installed inside the airtight structure discharges the substrate cooling gas supplied from the substrate cooling gas supply device 1400 to the inner surface of the cylindrical substrate 1112 via the valve 1401. Perform cooling. The substrate cooling gas that has undergone heat exchange is exhausted by a dedicated exhaust device 1402.

When a-Si (H, X) or the like is formed by the PCVD method, SiH ₄ , GeH ₄ , H ₂ , CH ₄ , B ₂ H ₆ , PH are used as a source gas, a dopant gas, and a dilution gas.
₃ mag is required. The raw material gas supply device 1200 includes a cylinder (not shown) for these raw material gases, a valve (not shown), and a mass flow controller (not shown). The raw material gas and the like supplied from the cylinder of each raw material gas and the like are adjusted to a predetermined flow rate by a mass flow controller, and a valve 126 provided immediately before the reaction vessel 1111 is provided.
0, the gas introduction pipe 1115 in the reaction vessel 1111
It is connected to the. The exhaust device 1300 is connected to the reaction vessel 11
A mechanism for controlling the pressure in the pressure 11 to a predetermined value is additionally provided.

Conventionally, the formation of a deposited film by the PCVD method is as follows.
Using the deposited film forming apparatus shown in FIG. 1, for example, the following procedure is performed.

First, a cylindrical substrate 1 is placed in a reaction vessel 1111.
The reactor 112 is installed, and the inside of the reaction vessel 1111 is exhausted by an exhaust device 1300 (for example, a diffusion pump). Subsequently, a substrate heating gas is introduced into the reaction vessel 1111 through the gas introduction pipe 1115. At this time, the mass flow controller (not shown) adjusts the introduced substrate heating gas to a predetermined flow rate. On the other hand, the reaction vessel 1
An exhaust valve (not shown) attached to the exhaust device 1300 while measuring the internal pressure of the reaction vessel 1111 with a vacuum gauge (not shown) so that the pressure inside the reactor 111 becomes a predetermined pressure selected to be, for example, 133 Pa or less. Adjust the aperture of

When the internal pressure is stabilized to a desired value by the above adjustment operation, for example, a high frequency power supply 1117 having a frequency of 105 MHz is set to a desired power, and high frequency power is introduced into the reaction vessel 1111 through a high frequency matching box 1118. . The high frequency power induces high frequency discharge / decomposition in the substrate heating gas to generate plasma.
The cylindrical substrate 1112 is heated by the heat energy from the generated plasma.

At the same time, a substrate cooling gas, for example, He, is supplied from a supply device 1400 to a cooling means 1114 provided inside the cylindrical substrate 1112 via a valve 1401. In the cooling means 1114, the supplied cooling gas is released into the cylindrical base 1112 as shown by the arrow in the figure,
It circulates inside the substrate while performing heat exchange, and is finally discharged by the exhaust device 1402. By adjusting the flow rate of the cooling gas to balance the heat energy supplied from the plasma with the amount of heat removed by the heat exchange of the cooling gas, the temperature of the cylindrical base 1112 is made uniform and controlled to a predetermined value. .

Conventionally, when the temperature of the cylindrical base 1112 reaches a predetermined temperature, the high-frequency power is once turned off. Then, the gas for heating the substrate and the source gas for forming a deposited film in the reaction vessel 1111 are exchanged. When this operation is completed and the flow rate of the raw material gas for forming the deposited film and the internal pressure have reached desired values, the high-frequency power supply 1117 is again set to the desired electric power to generate plasma, thereby starting deposition film formation. . Thereafter, a deposited film having a predetermined component composition on the cylindrical substrate 1112, for example, a-Si having a predetermined composition.
This is where deposited films such as (H, X) are formed. After the desired film thickness is formed, the supply of high frequency power is stopped,
Further, the flow of the source gas or the like into the reaction vessel 1111 is stopped, and the formation of the deposited film is completed. When a plurality of deposited films having different compositions are stacked, the above-described switching operation of the source gas is repeated a plurality of times to obtain a desired multilayer structure, for example, a charge injection blocking layer, a photoconductive layer, and a surface layer. A light receiving layer composed of a layer is formed.

With these techniques, the productivity of the deposited film has been improved, and the uniformity and characteristics have also been improved. Also, utilizing the good deposited film produced by the above-described conventional method,
Various semiconductor devices, photoconductors for electrophotography, line sensors for image input, imaging devices, photovoltaic devices, various other electronic elements, optical elements, and the like are on the market. However, the demand level in the market for products using these deposited films is increasing day by day, and to meet this demand, higher quality deposited films are required.

For example, in the case of an electrophotographic apparatus, there is an extremely strong demand for an improvement in copy speed, a reduction in the size of the electrophotographic apparatus, and a reduction in the price thereof. It is indispensable to improve the sensitivity and the like and to reduce the production cost of the photoreceptor. In recent years, digital electrophotographic apparatuses and color electrophotographic apparatuses, which have been remarkably popularized, frequently copy not only text originals but also photographs, pictures, design pictures, etc. Improvements in photoreceptor characteristics, such as reduction, have also been required more strongly than ever. With the aim of improving such photoconductor characteristics and reducing photoconductor production costs, optimization of deposition film formation conditions and deposition film stacking configuration itself has been further advanced, but at the same time, in terms of the deposition film formation method, Improvement is strongly desired.

[0015]

In view of such a situation, reconsidering the above-described conventional method of forming a deposited film,
At present, there is still room for improvement in relation to the improvement of the deposited film characteristics and the reduction of the deposited film formation cost.

For example, the uniformity of the characteristics of the deposited film to be formed
In terms of reproducibility, there is room for further improvement. Specifically, if the uniformity and reproducibility of the deposited film characteristics are not sufficiently high, in a configuration in which a plurality of deposited films are stacked, variations occur in the deposited film characteristics in each process, and the variations are integrated. Ultimately, this leads to a shortage of product quality and a decrease in the non-defective product rate. Further, in a configuration in which a plurality of deposited films are stacked, not only are the variations accumulated, but also because the functions of the plurality of layers are deeply related to each other, if the film characteristics of a certain layer deviate from the design values, Even if the film properties of the other layers are as designed, the expected performance is not exhibited at all, or the performance is synergistically reduced.

In the case of a member having a large area such as an electrophotographic photosensitive member, even if the film quality is extremely local or a point-like film defect is detected, only one defect is generated, and the entire member has a defect. Some can not be used at all.

As described above, improving the uniformity and reproducibility of the characteristics of the deposited film and suppressing the variation in the characteristics of the deposited film greatly improve the characteristics of the entire member using the deposited film and lower the manufacturing cost. It will contribute. In addition to improving the characteristics of the deposited film, realizing a method of forming a deposited film capable of improving the uniformity and reproducibility of the deposited film characteristics is necessary for optimizing the deposited film stacking configuration itself. It is indispensable to respond to market demands for higher standards.

The present invention solves the above problems,
An object of the present invention is to provide a method for forming a deposited film having excellent in-plane characteristics uniformity, and a method for forming a deposited film having uniform characteristics with high reproducibility. is there.

From a commercial point of view, an object of the present invention is to improve the reproducibility of a deposited film and to improve the productivity when producing a deposited film having uniform characteristics. It is an object of the present invention to provide a method for forming a deposited film, which enables the yield to be dramatically improved when mass production is performed. Another object of the present invention is to provide a method for forming a deposited film that can be easily mass-produced at a low cost in response to diversified deposited films.

[0021]

Means for Solving the Problems The present inventors have intensively studied to solve the problems left in the above-mentioned conventional method for forming a deposited film. As a starting point for that research,
When a deposited film is formed by a conventional deposited film forming method, a direct cause of variation in film characteristics of the deposited film, or
The identification of closely related phenomena was advanced. As a result of this study, it has been found that, for example, when a deposited film is formed by a conventional deposited film forming method using a deposited film forming apparatus as shown in FIG. 1, the following phenomenon occurs.

When the surface of the deposited film was observed, the occurrence of a structural defect called a spherical projection was confirmed.
It has been found that the areal density of structural defects called spherical projections varies in spite of forming a deposited film under the same conditions. Similarly, it was found that the characteristics of the deposited film varied even though the deposited film was formed under the same conditions.

It has been confirmed from a conventional study that this type of spherical projection starts to grow with foreign matter attached to the surface of the cylindrical substrate as a nucleus. In consideration of this point, conventionally, the cylindrical substrate before film formation is strictly cleaned, and is transported and mounted in the forming apparatus in a dust-controlled environment such as a clean room, so that dust is deposited on the cylindrical substrate. Attachment has been avoided as much as possible. Even in the case of a cylindrical substrate that is transported and mounted in the forming apparatus in such a clean state, the occurrence of structural defects called spherical projections is still often observed,
Further, since the frequency of occurrence varies, it is determined that there is a factor to which dust adheres even during formation of the deposited film.

It is presumed that dust adheres during the formation of the deposited film as follows. When the source gas is introduced into the discharge space and high-frequency power is introduced through the electrodes, the source gas is decomposed to form a deposited film on the cylindrical substrate. While the deposited film is deposited. The deposited film deposited on the substrate other than the substrate accumulates stress strain by receiving its own stress when forming the deposited film or receiving energy due to ion bombardment in the discharge space. When this stress strain is accumulated above a certain level, the deposited film is peeled off from the surface as a film piece,
It is thought that the particles scatter and diffuse in the discharge space, and a part of the particles adheres to the cylindrical substrate. That is, it is considered that fine film fragments generated inside the apparatus contaminate the deposited film on the cylindrical substrate, and spherical projections are generated.

It has been found that it is important to control the discharge state at the beginning of the deposition film formation in order to control the peeling of the film from each surface in the reaction vessel. The basis for reaching this conclusion is that the firing power varies with each deposition film formation.
Firstly, the film quality of the deposited film deposited in the initial stage of the deposition film formation in the reaction vessel varies. The initial deposited film is a portion which is in direct contact with each member in the reaction vessel, and the quality of the deposited film formed at this initial stage has a great effect on the adhesion between each member and the deposited film. Therefore, it is considered that if the discharge state in the initial stage of deposition film formation varies, the film quality of the deposition film formed in the initial stage also fluctuates, and further, the state of film peeling changes with each deposition film formation. . In addition, each surface in the reaction vessel on which the deposited film is formed may have different shapes, surface properties, materials, and the like in each part. Probably given.

Further, it is important to control the discharge state at the initial stage of the formation of the deposited film in controlling the peeling of the film from each surface in the reaction vessel. Another reason is that the deposited film is formed. A change in the temperature of each surface in the reaction vessel is considered. When plasma is generated to form a deposited film from a state where plasma is not formed, immediately after the plasma is generated,
Each surface receives heat from the plasma, causing a phenomenon in which the temperature suddenly rises. As described above, the film itself tends to accumulate stress strain inside the deposited film formed under the condition where the temperature changes transiently. In addition, strain is accumulated due to a change in the surface on which the deposited film is formed (mainly thermal expansion). As a result of the accumulated distortion, it is considered that film peeling is more likely to occur.

Based on these findings, further consideration was made, and it was considered that if the discharge state at the initial stage of the deposition film formation was made constant, the variation in the film quality of the deposition film formed at the initial stage could be effectively suppressed. As a result of examining measures to keep the discharge power at the beginning of the deposition film formation, specifically, the discharge power at the start of the deposition film formation, a plasma is generated in advance, and the deposition film is maintained while the plasma is maintained. By starting the supply of the forming source gas and starting the formation of the deposited film, it has been conceived that the discharge state at the initial stage of the deposited film formation can be kept constant. In addition, by generating plasma in advance before forming a deposited film, it is possible to prevent a rapid temperature change from occurring in the early stage of forming the deposited film, and to achieve a further preferable effect.

The present inventors considered the above idea, that is, to generate a plasma in advance, start supplying a deposition film forming source gas while maintaining the plasma, and start the formation of the deposition film. We searched for effective and specific procedures.
As a result, before the deposition film is formed, high-frequency power is introduced while supplying the substrate heating gas, plasma is generated, and the substrate is heated by the heat from the plasma. It has been found that when the substrate heating gas and the deposited film forming source gas are exchanged, the deposited film formation can be started while the plasma once generated is maintained. Further, it has been found that the variation in discharge power can be substantially eliminated during the exchange of the substrate heating gas and the deposited film forming source gas. Actually, it has been confirmed that when the formation of a deposited film is started according to this procedure, the frequency of occurrence of spherical projections is reduced, and the reproducibility thereof is also greatly improved. The present invention has been completed based on the above series of considerations and findings.

That is, according to the method of forming a deposited film of the present invention, in a reaction vessel that can be depressurized, a substrate is placed in the reaction vessel, and high-frequency power used for decomposition of a source gas for forming a deposited film is supplied from high-frequency power introduction means. A method for forming a deposited film on the substrate by supplying a source gas for forming a deposited film while introducing the deposited film, wherein the substrate is placed in the reaction vessel prior to forming the deposited film on the substrate. A heating gas and a high-frequency electric power are introduced to generate plasma in the reaction vessel, and the generated plasma is used to heat the substrate, and a substrate preheating step of setting the substrate temperature to a predetermined temperature is provided; Subsequent to the preheating step, while maintaining the plasma generated in the reaction vessel, the flow rate of the substrate heating gas is gradually reduced while the high-frequency power is continuously introduced, and the deposited film is formed. By gradually increasing the source gas flow rate, replacing the substrate heating gas and the deposited film forming source gas, and providing a gas replacement step of continuing to heat the substrate by plasma, at the end of the gas replacement step, A method for forming a deposited film, characterized in that a flow rate of a source gas for forming a deposited film reaches a predetermined value and a deposited film is continuously formed on the substrate without interrupting the introduction of high-frequency power.

In the method for forming a deposited film according to the present invention, the substrate is heated by heat from the plasma, and the plasma is maintained.
By exchanging the substrate heating gas and the deposition film forming source gas, the variation in the discharge power in the initial stage of deposition film formation is substantially eliminated, so that the frequency of occurrence of spherical projections is reduced, and the reproducibility is greatly improved. The effect of improving is obtained.

In the method of forming a deposited film according to the present invention, the substrate is heated by the heat from the plasma before the film is formed, and the film is formed by exchanging the substrate heating gas and the deposited film forming source gas while maintaining the plasma. Since the process is started, a change in temperature of not only the base but also various parts before and after the start of film formation can be suppressed. Even at the very beginning of the deposition film formation, the discharge power does not vary every time the deposition film is formed, and the film quality of the deposition film deposited in the reaction vessel at the early stage of the deposition film formation does not fluctuate. In this case, the temperature change is also suppressed, so that the effects of both act synergistically, and film peeling of the deposited film or the like deposited on each part of the reaction vessel hardly occurs.
It is considered that with the suppression of the adhesion of dust having a generation source in the reaction vessel, the areal density of the spherical projections was significantly reduced, and the variation was also reduced.

Further, in the method of forming a deposited film according to the present invention, in addition to the reduction in the surface density of the spherical projections and the variation thereof, the characteristics of the deposited film such as the charge retention ability are improved, and the reproducibility is also improved. did. This is considered to be due to the stabilization of the discharge accompanying the suppression of the film peeling described above. Alternatively, in addition to the stabilization of the discharge, since the substrate temperature is controlled to a substantially predetermined temperature in the initial stage of film formation, good deposited film formation proceeds, and microscopic structural disturbances This is considered to be an effect of improving the structural homogeneity of the entire film. By using this effect, for example, the characteristics and reproducibility of the light receiving member are improved,
In addition, it can be mass-produced inexpensively and easily in response to diversified light receiving members.

Further, when the method for forming a deposited film of the present invention is carried out under additional conditions described in the following (a) to (l), a more preferable result can be obtained.

(A) The substrate heating gas is selected from He or H ₂ .

(B) In the gas replacement step,
In the exchange of the substrate heating gas and the deposited film forming source gas, the change in the flow rate of the substrate heating gas and the change in the flow rate of the deposited film forming source gas are simultaneously completed.

(C) In the gas replacement step,
In the exchange of the substrate heating gas and the deposited film forming source gas, the flow rate of the substrate heating gas ends before the end of the flow rate change of the deposited film forming source gas.

(D) At least before the completion of the gas replacement step, the substrate is heated by plasma on the outer surface, and the substrate is cooled from the inner surface of the substrate not directly heated by plasma.

(E) The cooling of the base is performed by a direct heat conduction system.

(F) The cooling of the substrate is at least
At the time when the gas replacement process is started, the process is performed.

(G) The change in substrate temperature during the gas replacement step is | 30 | ° C. or less.

(H) The time required for the gas replacement step is selected in the range of 10 seconds to 30 minutes.

(I) The frequency of the high frequency power is 50
MHz to 450 MHz.

(J) The deposited film deposited on the substrate is
This is for forming an electrophotographic photosensitive member.

(K) A reaction region separation container made of a dielectric member is set in the reaction container, a high-frequency introducing means is provided outside the reaction region separation container, and the base is placed inside the reaction region separation container. Arranged, supply of the substrate heating gas and the deposition film forming source gas is performed inside the reaction region separation container, and high frequency power is supplied from the high frequency introduction means, and plasma is supplied inside the reaction region separation container. Cause.

(L) A plurality of substrates are placed in the reaction vessel, and a deposited film is formed on at least two or more substrates simultaneously.

[0046]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the method of forming a deposited film according to the present invention, a substrate heating gas and high-frequency power are introduced into a reaction vessel, and the substrate is heated by the generated plasma to bring the substrate temperature to a predetermined temperature. A substrate preheating step, and a step of setting a flow rate of a source gas for forming a deposited film to a predetermined amount, decomposing the source gas by plasma induced by high frequency power, and forming a deposited film having a desired composition on the substrate. In the meantime, while maintaining the plasma generated in the reaction vessel, the flow rate of the substrate-heating gas is gradually reduced while the high-frequency power is continuously introduced to maintain the plasma generated in the reaction vessel. A gas replacement step in which the flow rate is gradually increased and the substrate heating gas and the deposition film forming source gas introduced into the reaction vessel are exchanged, and the substrate is continuously heated by the plasma during that time. In that provision, the most important feature. At the end of the gas replacement step, a source gas for forming a deposited film required in the next deposited film forming step is supplied at a predetermined flow rate. During this time, the substrate heating gas and the deposited film forming source gas are present in the reaction vessel in a mixed manner. If the substrate heating gas is reactive to the deposited film forming source gas, or if it remains in the reaction vessel, it is taken into the next deposited film or becomes unnecessary doping gas. If it does, it leaves the possibility of having an effect that greatly offsets the effect of the present invention. Therefore, the substrate heating gas includes an inert gas or a deposited film that is not taken into the next deposited film and does not act as an unnecessary doping gas even when remaining in the reaction vessel. It is usual to use a gas used as a dilution gas in the forming source gas. Specifically, in a normal PCVD method,
He, N ₂ , Ar, H _{2, and the} like are gases that can generate stable plasma, but have no substantial effect when remaining in the reaction system as described above. Therefore, it is preferable to select the substrate heating gas from He, N ₂ , Ar, and H ₂ . Among them, H ₂ and He are commonly used as diluent gases, and therefore, in the method of the present invention, it is more preferable to use He or H ₂ or a mixture thereof as the substrate heating gas.

In the gas replacement step, it is more preferable that the change in the flow rate of the base material heating gas and the change in the flow rate of the deposition film formation raw material gas are simultaneously completed in the replacement of the base heating gas and the deposition film formation source gas. . It is also possible to adopt a mode in which the change in the flow rate of the substrate heating gas ends before the change in the flow rate of the deposition film forming source gas ends.
In this case, it is preferable that the change in the flow rate of the source gas for forming a deposited film has been half or more at the time when the change in the flow rate of the substrate heating gas is completed. That is, although the flow rate of the gas introduced into the reaction vessel changes transiently, it is preferable to make the change gentle so that the plasma generated in the system does not suddenly fluctuate.

In the method for forming a deposited film of the present invention, plasma is maintained during the gas replacement step, and the heating of the substrate by the plasma is not interrupted, but the plasma is supplied in the substrate preheating step and the deposited film forming step. There is a difference in the heat energy to be used. The gas replacement process is in a transitional state, and in order to sufficiently achieve the effects of the present invention, it is necessary to keep the substrate temperature from deviating significantly from the desired temperature even during this period. Therefore, it is preferable to control the temperature of the substrate by cooling the substrate by cooling means provided on the inner surface (the surface not exposed to the plasma) of the substrate.

Further, it is preferable that the cooling of the substrate has a quick response. Therefore, the cooling means provided on the inner surface (the surface not exposed to plasma) of the substrate performs heat exchange by a direct heat conduction method. Are preferred. For example, a method in which a cooling gas is directly supplied as a heat exchange medium to the inner surface of the substrate to perform heat exchange by heat conduction is excellent in responsiveness and is more preferable.

In the method for forming a deposited film according to the present invention, it is preferable that the cooling of the substrate is started at least at the start of the gas replacement step. In other words, it is preferable that the cooling means be made to function by the time when the exchange of the substrate heating gas and the deposited film forming source gas is started.

On the other hand, in the method of forming a deposited film according to the present invention, a sudden temperature change is prevented from occurring when the deposition film formation is started by providing a gas replacement step.
If there is a large difference between the substrate preheating step and the substrate temperature during the formation of the deposited film, each of the members installed in the reaction vessel also involves a considerable temperature change in the initial stage of the deposited film formation. That is, the effects of the present invention are considerably offset. Therefore, it is preferable to select conditions under which there is no significant difference between the substrate preheating step and the substrate temperature during the formation of the deposited film. For example, the change in the substrate temperature during the gas replacement step, that is, the change in the substrate temperature during the formation of the deposited film from the end of the heating of the substrate is preferably | 30 | (° C.) or less.

Furthermore, in the method for forming a deposited film of the present invention, the provision of the gas replacement step moderates the transient change in the plasma state in the reaction vessel. Is necessary to some extent. Although it depends on the difference between the substrate preheating step and the substrate temperature during the deposition film formation, or the difference between the introduced gas flow rate and the high-frequency power, at least the time required for the gas replacement step is preferably 10 seconds or more. . However,
It is not necessary to take a very long time, and even when there are considerable differences in the conditions such as the substrate preheating step and the substrate temperature during the deposition film formation, the flow rate of the introduced gas, and the high-frequency power, it is preferable not to exceed 30 minutes. . Therefore, it is preferable to select the time required for the gas replacement step in the range of 10 seconds to 30 minutes.

Further, in the method of forming a deposited film according to the present invention, it is preferable to select the frequency of the high-frequency power in the range of 50 MHz to 450 MHz. In particular, as shown in a specific example described later, when forming a-Si (H, X) or the like by the PCVD method, it is more preferable to select the above-mentioned frequency range.

The method of forming a deposited film according to the present invention can be suitably applied when forming a-Si (H, X) or the like by the PCVD method. Specifically, an electrophotographic photosensitive member is formed on a substrate. In this case, it can be suitably applied.

Further, in the method for forming a deposited film according to the present invention, a reaction region separation container made of a dielectric member is provided inside a reaction container, and a high frequency introducing means is provided outside the reaction region separation container, This is a more preferable method when a high-frequency power is supplied from a means to form a deposited film on the substrate.

Further, in the method for forming a deposited film of the present invention, it is preferable that a plurality of the substrates are arranged in a reaction vessel. That is, since spherical projections and the like due to dust generation are effectively suppressed, the defect occurrence rate is significantly reduced, and as a result, productivity can be improved by forming a deposited film on a plurality of substrates simultaneously.

Hereinafter, the procedure of the method of the present invention will be described more specifically with reference to figures and the like to facilitate understanding.

By applying the method for forming a deposited film of the present invention,
For example, when a conventional deposition film forming apparatus shown in FIG. 1 is used, the deposition film formation by the VD method can be performed by the following procedure.

First, the cylindrical substrate 1 is placed in the reaction vessel 1111.
The reactor 112 is installed, and the inside of the reaction vessel 1111 is exhausted by an exhaust device 1300 (for example, a diffusion pump). Subsequently, a substrate heating gas is introduced into the reaction vessel 1111 through the gas introduction pipe 1115. At this time, the mass flow controller (not shown) adjusts the introduced substrate heating gas to a predetermined flow rate. On the other hand, the reaction vessel 1
An exhaust valve (not shown) attached to the exhaust device 1300 while measuring the internal pressure of the reaction vessel 1111 with a vacuum gauge (not shown) so that the pressure inside the reactor 111 becomes a predetermined pressure selected to be, for example, 133 Pa or less. Adjust the aperture of

When the internal pressure is stabilized by the above adjustment operation, for example, the high-frequency power supply 111 having a frequency of 105 MHz is used.
7 is set to a desired power, and high-frequency power is introduced into the reaction vessel 1111 through the high-frequency matching box 1118. The high frequency power induces high frequency discharge / decomposition in the substrate heating gas to generate plasma. The thermal energy from the generated plasma causes the cylindrical substrate 11
12 is heated.

At the same time, a substrate cooling gas, for example, He, is supplied from the supply device 1400 to the cooling means 1114 provided inside the cylindrical substrate 1112 via the valve 1401. In the cooling means 1114, the supplied cooling gas is released into the cylindrical base 1112 as shown by the arrow in the figure,
It circulates inside the substrate while performing heat exchange, and is finally discharged by the exhaust device 1402. By adjusting the flow rate of the cooling gas to balance the heat energy supplied from the plasma with the amount of heat removed by the heat exchange of the cooling gas, the temperature of the cylindrical base 1112 is made uniform and controlled to a predetermined value. .

Next, when the temperature of the cylindrical substrate 1112 reaches a predetermined temperature, the replacement of the substrate heating gas and the deposition film forming source gas in the reaction vessel 1111 is started. That is, in the gas replacement step, the flow rate of the substrate heating gas is reduced, and the flow rate of the deposited film forming source gas is gradually increased. During this time, the high frequency power is continuously introduced to maintain the plasma. Further, the pressure in the reaction vessel 1111 is gradually adjusted in accordance with the change in the total gas flow rate accompanying the replacement of the gas, so that the internal pressure finally matches the internal pressure to be set in the next deposition film forming step. Similarly, the power amount of the high-frequency power to be introduced is also gradually adjusted according to the change in the total gas flow rate due to the replacement of the gas, and finally coincides with the power amount of the high-frequency power to be set in the next deposition film forming step. To do. At this time, if there is a difference in the substrate temperature to be set between the former substrate preheating step and the next deposited film forming step, the cooling gas flow rate is also adjusted in addition to the above-mentioned transition change of the high-frequency electric power amount. Thus, the substrate temperature is gradually set to the set value. The flow rate of each gas at the time of replacement is controlled by a mass flow controller (not shown).

By the above-described changes in the gas flow rates and the accompanying adjustment of the pressure in the reaction vessel and the amount of the high-frequency power, there is a transitional change in the plasma state, but the change can be made gentle. Transient changes in temperature are more gradual. When the supply of the substrate heating gas is stopped and the gas flow rate of the deposition film forming raw material gas, the pressure in the reaction vessel, and the amount of high-frequency power reach the values set in the next deposition film formation step, This gas replacement step is completed, and the process proceeds to the deposited film forming step without interruption.

Thereafter, a deposited film having a predetermined component composition, for example, a film having a predetermined composition, is formed on the cylindrical substrate 1112.
This is where a deposited film of -Si (H, X) or the like is formed. After the formation of the desired film thickness, the supply of the high-frequency power is stopped, the flow of the raw material gas for forming the deposited film into the reaction vessel 1111 is stopped, and the formation of the deposited film is completed. When a plurality of deposited films having different compositions are stacked, the above-described switching operation of the source gas is repeated a plurality of times to obtain a desired multilayer structure, for example, a charge injection blocking layer, a photoconductive layer, and a surface layer. A light receiving layer composed of a layer is formed.

When stacking a plurality of deposited films, all valves other than the necessary gas are closed when forming each layer. In addition, unnecessary gas remains in the pipe from the valve to the reaction vessel 1111, and unnecessary gas remaining in the pipe flows into the reaction vessel 1111, and the reaction vessel 1111 If necessary, before starting the formation of the next layer deposited film, fully open the exhaust valve (not shown) in advance, and once evacuate the system to a high vacuum, in order to avoid remaining in the system. To discharge a small amount of gas remaining in the piping. During the formation of the deposited film, the motor 1120 is driven to rotate the rotating shaft 112.
2 is rotated, and the cylindrical support 1112 as the base is rotated. Due to the rotation of the substrate, the heating from the plasma becomes uniform, and the thickness of the deposited film and the distribution of the film characteristics in the circumference become uniform.

In order to further enhance the functions and effects of the above-described method for forming a deposited film of the present invention, it is more preferable to carry out the method in such a manner that the following conditions are also satisfied.

First, in the method of the present invention, He gas is used as the substrate heating gas used in the substrate preheating step because it is easy to handle and there is no concern that contamination or the like will occur even if it remains in the reaction vessel. , N ₂ , Ar, and H ₂ are preferably used. In the method of the present invention, the flow rate of the substrate heating gas is reduced during the gas replacement step, and the supply is stopped before the next deposited film forming step. However, a small amount of the substrate heating gas remains in the pipe section between the valve provided in the pipe and the reaction vessel. He, N ₂ , A
When a gas selected from r and H ₂ is used, it is possible to substantially eliminate the influence of the remaining substrate heating gas.
For example, when a deposited film made of a-Si (H, X) is formed as described above, the influence on the deposited film is further reduced so that the deposited film is also used as a diluent gas of a source gas for forming a deposited film. Therefore, it is more preferable to use He or H ₂ , or a mixture of both.

In the method of the present invention, heat from the plasma maintained in the reaction vessel is used to heat the substrate.
The feature (action) of the method of the present invention is that the plasma state in the reaction vessel is stably maintained without a significant change from the substrate preheating step to the deposited film forming step through the gas replacement step. As long as it is achieved, a heat source other than the heat from the plasma can be used for heating the substrate. Furthermore, as a main heat source used for heating the substrate, a heat source other than the heat from the plasma may be used. In other words, depending on the film forming conditions for forming the deposited film, when only the heat from the plasma is significantly insufficient to maintain the desired substrate temperature, another heat source is mainly used to achieve the desired substrate temperature. It is good also as a structure which performs.

In particular, in the method of the present invention, deposits additionally deposited on various members arranged in the reaction vessel other than the substrate are separated and dusted and scattered in the reaction vessel. Prevention is an important factor. Above all, it is an important element to suppress the transitional temperature change in various members that induces the above-mentioned separation and dusting. At this time, it is effective to avoid a large change in thermal energy from the plasma and a transient and rapid up and down movement from the substrate preheating step to the deposited film forming step through the gas replacement step. For example, from the substrate preheating step, through the gas replacement step, to the deposited film forming step, the thermal energy from the plasma is kept constant, and the amount of heat supplied from another heat source used together is adjusted to obtain the desired substrate temperature. If such a configuration can be adopted, it is often more preferable.

As described above, in addition to the heating by the plasma, the heating by the other heat source may be used in combination with the heating of the substrate. However, if the heating is performed only by the plasma, the configuration of the apparatus is simplified, and as a result, In general, it is preferable to perform heating by plasma from the initial stage of heating, because reduction in apparatus cost and easiness of maintenance can be achieved.

When the heating means other than the plasma heating is used in combination as described above, the heating means to be used may be a controllable heating element, specifically, a winding heater of a sheath-like heater, a plate-like heater, or the like. Examples of the heating element include an electric resistance heating element such as a heater and a ceramic heater, a heat radiation lamp heating element such as a halogen lamp and an infrared lamp, and a heating element formed by a heat exchange unit using a liquid, a gas or the like as a temperature medium.

In the substrate preheating step, the flow rate of the substrate heating gas, the internal pressure, and the value of the high-frequency power are appropriately set in accordance with the required substrate surface temperature, temperature rising time, discharge stability, and the like.

The method of exchanging the heating gas and the source gas for forming the deposited film in the gas exchanging step is not particularly limited as long as the plasma can be maintained during that time. However, as shown in FIG. It is generally preferable that the change in the gas flow rate and the change in the flow rate of the deposition film forming source gas end at the same time. This means that if the flow rate changes of both gases end at the same time, the flow rate changes of each gas will be performed individually.
As a whole, the gas flow rate change can be made more gradual, and it becomes easier to suppress plasma turbulence due to the gas flow rate change. Along with that, the reproducibility is improved,
Generally preferred. Alternatively, as shown in FIG. 2B, prior to the end of the change in the flow rate of the deposition film forming source gas,
In some cases, it is more preferable to end the change in the flow rate of the substrate heating gas. For example, the effect of the gas for heating the substrate remaining in the reaction vessel on the deposited film can be reduced, which may be more preferable in terms of stability of the film characteristics. Furthermore, as shown in FIG. 2C, when one of the substrate heating gas and the deposition film forming source gas is the same type of gas, the flow rate of the substrate heating gas is adjusted and the deposition film formation is performed as it is. It may be used as a part of the raw material gas.

If the internal pressure and / or the high-frequency power during the substrate preheating step and the deposition film forming step are different from each other, the respective values are adjusted to predetermined values at the end of the substrate preheating step or at the start of the deposition film forming step. Although it is possible, as shown in FIG. 2 (D), it is preferable to gradually adjust each to a predetermined value in conjunction with the change in the gas flow rate during the gas replacement step. That is, if the difference between the internal pressure and / or the high-frequency power is relatively small, the adjustment at the end of the substrate preheating step has only a slight effect on the plasma state. If it is suddenly changed, the state of the plasma also greatly changes. If there is a large change in the plasma state at the end of the gas replacement step or at the start of the deposited film formation step, a considerable temperature change is caused in the early stage of the deposited film formation, and the effect of the present invention is greatly reduced. Therefore, by gradually adjusting the internal pressure and / or the high-frequency power to a predetermined value along with the replacement of the gas, it is possible to effectively suppress a rapid change in the plasma, which is more preferable.

If the time required for the gas replacement step is too long, it is not preferable in terms of productivity. On the other hand, if the time is too short, a rapid change of plasma occurs, so that the effect of the present invention cannot be sufficiently exhibited. Usually, the time required for the gas replacement step depends on the conditions at the time of forming the deposited film.
It is preferable to select an appropriate value from 10 seconds to 30 minutes in consideration of the conditions at the time of forming the deposited film.

Conventionally, for the purpose of controlling the temperature of the substrate,
The outer surface of the substrate is exposed to the plasma, and while being heated by the heat from the plasma, the substrate is cooled from the inner surface of the substrate that is not directly heated by the plasma. Also in the method of the present invention, it is preferable that the temperature of the substrate is controlled by cooling the substrate from the inner surface of the substrate while being heated by the heat from the plasma. Compared with the conventional method, in the method of the present invention, the plasma state is maintained stably, and the temperature change of the substrate at the time of gas replacement and the temperature change of the substrate at the initial stage of deposition film formation are greatly suppressed. But, from the inner surface of the base,
By cooling the substrate, it is easier to control and it is preferable to improve the characteristics of the obtained deposited film.

The means used for this purpose, for example, the cooling means 1114 in FIG. 1 may be any heat-absorbing body that can easily exchange heat. Specifically, a liquid, a gas or the like is used as a cooling medium. A flowing means can be used, and examples thereof include a cooling coil, a cooling plate, and a cooling cylinder. Further, as a cooling method, any of an indirect cooling method of absorbing radiant heat from the substrate and a direct heat conduction method of contacting a cooling means directly with the substrate may be used, but in general, from the viewpoint of heat exchange efficiency. The direct heat conduction method is more preferable, and the heat exchange efficiency is superior. Therefore, rapid cooling and control of the cooling amount are possible, and the temperature change of the base can be reduced.

Specific examples of the direct heat conduction method that can be used in a limited space such as the inner surface of the substrate include a method in which a cooling gas is introduced into the substrate and brought into contact with the substrate to perform cooling, and a member made of metal is attached to the inner surface of the substrate. For example, a method of mechanically contacting and cooling. Generally, from the viewpoint of controllability of the cooling amount, the former means for controlling the flow rate of the cooling gas serving as the heat medium is more preferable. As the cooling gas, a gas selected from He, N ₂ , Ar, and H ₂ may be used because it is easy to handle and does not cause contamination if the gas leaks into the reaction vessel. preferable. Particularly, from the viewpoint of cooling efficiency, it is more preferable to use He and H ₂ having high thermal conductivity.

The cooling of the substrate may be performed at the same time as the heating of the substrate. However, in order to suppress the temperature change at the time of gas replacement and the initial stage of deposition film formation, and to shorten the heating time,
It is more preferable to start the process from the start of exchanging the substrate heating gas and the deposited film forming source gas.

In the present invention, it is preferable to control the change in the substrate temperature at the time of replacing the gas to | 30 | (° C.) or less in order to improve the characteristics of the deposited film. It is considered that the deposited film formed in a situation where the temperature change is large accumulates stress strain inside, so that the characteristic improvement is suppressed.

The method of forming a deposited film of the present invention has a large surface area which is disposed in a reaction vessel in close proximity to a substrate, is heated by plasma, and has a large amount of deposited film or deposit deposited on its surface. It is more effective in a device where a member exists. For example, in the deposited film forming apparatus of the form shown in FIG. 3, the reaction region separation container wall disposed in the reaction container corresponds to the member having the large surface area,
When the deposited film forming apparatus having the form shown in FIG. 3 is used, the deposited film forming method of the present invention is more effective.

FIG. 3 is a diagram showing an apparatus configuration suitable for carrying out the deposited film forming method of the present invention. Hereinafter, the configuration of the deposited film forming apparatus shown in FIG. 3 and the deposited film forming method of the present invention will be described. A procedure for forming a deposited film using the deposited film forming apparatus shown in FIG. 3 will be described. FIG. 3A is a longitudinal sectional view schematically showing a deposited film forming apparatus, and FIG. 3B is a transverse sectional view schematically showing the deposited film forming apparatus. Like the device shown in FIG. 1, the device shown in FIG.
Broadly speaking, it consists of three types of device parts, and the deposition device 310
0, source gas supply device 3200, reaction zone separation vessel 3
An exhaust device 3500 for reducing the pressure inside 400 is provided. The deposition apparatus 3100 includes a reaction region separation container 34 made of a dielectric member installed in the reaction container 3111.
00 and a space B sandwiched between a reaction vessel 3111 and a reaction area separation vessel 3400 made of the dielectric member. In the space A in the reaction region separation container 3400 made of the dielectric member, a substrate holder 3113 is provided.
Cylindrical base 3112 and gas inlet pipe 3115 attached to
Is installed. Further, a cathode electrode 3116 is provided in a space B sandwiched between the reaction container 3111 and the reaction region separation container 3400 made of a dielectric member. A high-frequency power supply 3117 is connected to the cathode electrode 3116 via a high-frequency matching box 3118. The cylindrical substrate 3112 mounted on the substrate holder 3113 has a structure to be cooled by substrate cooling means (not shown), as in the apparatus of FIG. Further, the base holder 3113 is connected to the rotation mechanism 3122, and is rotated by the rotation drive unit 3120. The cylindrical substrate 3112 is configured to be mounted on the substrate holder 3113 so as to keep airtight with respect to the reaction region separation container 3400 depressurized by the exhaust device 3500.

When a-Si (H, X) or the like is formed by the PCVD method, SiH ₄ , GeH ₄ , H ₂ , CH ₄ , B ₂ H ₆ , PH are used as a source gas, a dopant gas, and a dilution gas.
₃ mag is required. The source gas supply device 3200 includes a cylinder (not shown) for these source gases and the like, a valve (not shown), and a mass flow controller (not shown). The raw material gas or the like supplied from the cylinder of each raw material gas or the like is adjusted to a predetermined flow rate by a mass flow controller, and is supplied to a gas introduction pipe 3115 in the reaction region separation container 3400 via a valve 3260 provided immediately before the reaction region separation container 3400. It is connected. Exhaust device 3300
Is provided with a mechanism for controlling the pressure in the reaction region separation vessel 3400 to a predetermined value.

A procedure for forming a deposited film using the deposited film forming apparatus shown in FIG. 3 according to the deposited film forming method of the present invention is performed, for example, as follows.

First, in a dust-controlled environment such as a clean room, the cylindrical substrate 3112 is mounted in the apparatus.
The cylindrical substrate 3112 is mounted on the substrate holder 3113 located in the reaction region separation container 3400 made of a dielectric member and installed in the reaction container 3111. The reaction vessel 3111 is closed, and the inside of the reaction area separation vessel 3400 is evacuated by the exhaust device 3300 (for example, a diffusion pump). Subsequently, a substrate heating gas is introduced into the reaction region separation container 3400 via the gas introduction pipe 3115. At this time, the mass flow controller (not shown) adjusts the introduced substrate heating gas to a predetermined flow rate. On the other hand, while measuring the internal pressure of the reaction region separation container 3400 with a vacuum gauge (not shown) so that the pressure in the reaction region separation container 3400 becomes a predetermined pressure selected to be, for example, 133 Pa or less,
The opening of an exhaust valve (not shown) attached to the exhaust device 3300 is adjusted.

When the internal pressure is stabilized by the above adjustment operation, for example, a high-frequency power supply 311 having a frequency of 105 MHz is used.
7 is set to a desired power, and high-frequency power is introduced into the reaction vessel 3111 through the high-frequency matching box 3118. The introduced high-frequency power reaches the inside of the reaction region separation container 3400 made of a dielectric member, and high-frequency discharge / decomposition is induced in the substrate heating gas under reduced pressure to generate plasma.
The cylindrical substrate 3112 is heated by the heat energy from the generated plasma.

At the same time, a substrate cooling gas, for example, He, is supplied to a cooling means provided inside the cylindrical substrate 3112. The supplied cooling gas is released into the cylindrical substrate 3112, circulates inside the substrate while performing heat exchange, and is finally discharged out of the reaction vessel 3111. By adjusting the flow rate of the cooling gas to balance the heat energy supplied from the plasma with the amount of heat that the cooling gas exchanges and removes, the temperature of the cylindrical base 3112 is made uniform and controlled to a predetermined value. .

Next, when the temperature of the cylindrical substrate 3112 reaches a predetermined temperature, the exchange of the substrate heating gas and the deposition film forming source gas in the reaction region separation container 3400 is started. That is, in the gas replacement step, the flow rate of the substrate heating gas is reduced, and the flow rate of the deposited film forming source gas is gradually increased. During this time, the high frequency power is continuously introduced to maintain the plasma. Further, the pressure in the reaction region separation container 3400 is gradually adjusted in accordance with the change in the total gas flow rate due to the replacement of the gas so that the internal pressure finally matches the internal pressure to be set in the next deposited film forming step. . Similarly, the power amount of the high-frequency power to be introduced is also gradually adjusted according to the change in the total gas flow rate due to the replacement of the gas, and finally coincides with the power amount of the high-frequency power to be set in the next deposition film forming step. To do. At that time, if there is a difference in the substrate temperature to be set between the former substrate preheating step and the next deposited film forming step, in addition to the above-mentioned transition change of the high-frequency electric power amount,
The cooling gas flow rate is also adjusted so that the temperature of the substrate gradually reaches the set value. The flow rate of each gas at the time of replacement is controlled by a mass flow controller (not shown).

By the above-described changes in the gas flow rates and the accompanying adjustment of the pressure in the reaction vessel and the amount of the high-frequency power, there is a transient change in the plasma state, but the change can be made gentle. Transient changes in temperature are more gradual. When the supply of the substrate heating gas is stopped and the gas flow rate of the deposition film forming raw material gas, the pressure in the reaction vessel, and the amount of high-frequency power reach the values set in the next deposition film formation step, This gas replacement step is completed, and the process proceeds to the deposited film forming step without interruption.

Thereafter, a deposited film having a predetermined component composition, for example, a film having a predetermined composition is formed on the cylindrical substrate 3112.
This is where a deposited film of -Si (H, X) or the like is formed. After the formation of the desired film thickness, the supply of the high-frequency power is stopped, the flow of the raw material gas for forming the deposited film into the reaction region separation vessel 3400 is stopped, and the formation of the deposited film is completed. When a plurality of deposited films having different compositions are stacked, the above-described switching operation of the source gas is repeated a plurality of times to obtain a desired multilayer structure, for example, a charge injection blocking layer, a photoconductive layer, and a surface layer. A light receiving layer composed of a layer is formed.

In the apparatus shown in FIG. 3, a reaction region separation vessel 3400 made of a dielectric member is provided in a reaction vessel 3111, and a plasma discharge space is formed in the reaction region separation vessel 3400.
The major feature is that the configuration is limited to only the inside of the. By providing this reaction region separation container, it is possible to greatly improve the utilization efficiency of the raw material gas. Unlike the conventional device shown in FIG. 1 in which the discharge space wall is made of metal, the device shown in FIG. 3 uses a dielectric member as the container wall that separates the plasma discharge space. The area of the ground portion in the discharge space is significantly reduced. Accordingly, when the same high-frequency power is applied, the plasma potential in the apparatus shown in FIG. 3 is higher than that in the apparatus shown in FIG. Using the apparatus shown in FIG. 3, a conventional method for forming a deposited film is performed.
When the operation for generating the plasma is performed again, the influence of the variation in the electric power for starting the discharge becomes more remarkable. On the other hand, in the method of forming a deposited film according to the present invention, when the deposition film formation is started, there is substantially no variation in the electric power at the start of discharge. Therefore, when the apparatus shown in FIG. 3 is used, the effect becomes clearer. Therefore,
As in the apparatus shown in FIG. 3, even if the vessel wall that separates the plasma discharge space is located relatively close to the substrate, the variation in the discharge starting power or the effect of the rapid temperature rise when the plasma is generated. Avoided effectively.

In the apparatus shown in FIG. 3, as a material for forming the reaction region separation vessel 3400 and a dielectric member, any material can be used as long as it has a small loss of high frequency. For example, alumina, titanium dioxide, aluminum nitride, boron nitride, zirconium , Cordierite, zircon cordierite, silicon oxide, beryllium oxide mica-based ceramics, quartz glass, Pyrex (registered trademark) glass, and Teflon (registered trademark). Further, these may be used alone or in combination. Among the materials exemplified above, in terms of less absorption of high frequency,
Alumina, boron nitride, quartz glass, and Teflon are preferred, and alumina and quartz glass are more preferred because they are excellent in strength, durability, and corrosion resistance.

The shape of the reaction region separation vessel 3400 made of a dielectric member is not particularly limited as long as high-frequency power can be effectively and uniformly introduced into the inside thereof. When the gas inlet tube and the cathode electrode are located symmetrically, as in the apparatus shown in FIG. 3, the cylindrical or regular polygonal tube is preferably used. Of these, a cylindrical shape is more preferable in terms of uniformity of discharge.

The wall thickness of the reaction region separation vessel 3400 made of the above-mentioned dielectric member is not particularly limited as long as an excessive loss of high-frequency power is not caused, but it is desirable to make the wall thickness as thin as possible in terms of cost and handling. On the other hand, a certain thickness is required in terms of strength and durability. Although the thickness differs depending on the cross-sectional shape, length and diameter, generally there is no problem in strength and durability if the thickness is at least 1 mm or more, preferably 5 mm or more.

On the other hand, as described above, the reaction region separation container 3400 made of a dielectric member is close to the base,
Deposition of the deposited film occurs on its inner surface. Regarding the surface properties of the reaction zone separation vessel, there is no particular limitation on the outer surface, but on the inner surface (the surface facing the space A), a smooth surface such as a mirror surface is required to improve the adhesion of the deposited film. It is generally preferred that the surface be slightly rougher than that, since the surface area in contact with the deposited film can be increased. However, if the surface is made too rough to increase the surface area, the amount of dust attached will increase. Therefore, a surface having moderate unevenness is preferable. For example, the surface property is preferably 5 to 200 μm, and 10 to 90 μm in terms of ten-point average roughness (Rz).
Is more preferred. Further, the surface properties are preferably uniform. If the difference between the maximum value and the minimum value of Rz within the wall surface is within 100 μm, there is no practical problem.

The method for forming a deposited film according to the present invention is, for example, shown in FIG.
It is even more effective when a plurality of substrate holders are provided in a reaction vessel using the apparatus as shown in (1) and a deposited film is formed on a plurality of substrates in the same step.

FIG. 4A is a longitudinal sectional view schematically showing a deposited film forming apparatus, and FIG. 4B is a transverse sectional view schematically showing the deposited film forming apparatus. Similar to the apparatus shown in FIG. 3, the apparatus shown in FIG. 4 is roughly divided into three types of apparatus parts, and is used to reduce the pressure inside the deposition apparatus 4100, the raw material gas supply apparatus 4200, and the reaction region separation vessel 4400. Of the exhaust device 4500. Stacking device 4
Reference numeral 100 denotes a space A corresponding to the inside of a reaction region separation container 4400 formed of a dielectric member provided in the reaction container 4111, and a space B sandwiched between the reaction container 4111 and the reaction region separation container 4400 formed of the dielectric member. . A cylindrical substrate 4112 mounted on a plurality of substrate holders 4113 and a gas introduction pipe 4115 are provided at the center in a space A in the reaction region separation container 4400 made of the dielectric member. The space B sandwiched between the reaction vessel 4111 and the reaction region separation vessel 4400 made of a dielectric member includes
A cathode electrode 4116 is provided. The high-frequency matching box 4 is further provided with respect to the cathode electrode 4116.
A high frequency power supply 4117 is connected via 118.

The cylindrical substrate 4112 mounted on the substrate holder 4113 is structured to be cooled by the substrate cooling means as in the apparatus shown in FIG. The substrate cooling means 4114 installed inside the airtight structure is provided with a valve 44.
The substrate cooling gas supplied from the substrate cooling gas supply device through 01 is discharged to the inner surface of the cylindrical substrate 4112 to perform cooling. The substrate cooling gas that has undergone heat exchange is
The air is exhausted by the exclusive exhaust device 4402.

The base holder 4113 is connected to a rotation mechanism 4122, and is rotated by a rotation drive unit 4120. The cylindrical substrate 4112 is provided with the exhaust device 45.
The reaction region separation container 4400, which is decompressed by the pressure of 00, is mounted on the base holder 4113 so as to maintain airtightness.

When a-Si (H, X) or the like is formed by the PCVD method, SiH ₄ , GeH ₄ , H ₂ , CH ₄ , B ₂ H ₆ , PH are used as a source gas, a dopant gas, and a diluent gas.
₃ mag is required. The source gas supply device 4200 includes a cylinder (not shown) for these source gases and the like, a valve (not shown), and a mass flow controller (not shown). The raw material gas or the like supplied from the cylinder of each raw material gas or the like is adjusted to a predetermined flow rate by a mass flow controller, and is supplied to a gas introduction pipe 4115 in the reaction region separation container 4400 via a valve 4260 provided immediately before the reaction region separation container 4400. It is connected. Exhaust device 4300
Is provided with a mechanism for controlling the pressure in the reaction region separation container 4400 to a predetermined value.

Thus, the apparatus of FIG. 4 has the same configuration as the apparatus of FIG. 3, except that a plurality of substrate holders are provided in the reaction vessel.

In the conventional method of forming a deposited film, the main cause of the variation in the characteristics of the deposited film is, as described above, the variation in the electric power for starting the discharge when the deposition of the deposited film is started. It is thought that the electric power at the start of discharge is also affected by differences in the arrangement, shape, or surface condition of components in the reaction vessel, but it is not technically easy to maintain them strictly, and It is also difficult in terms of workability and cost. Therefore, in the conventional method, the reproducibility of the discharge starting power is not sufficient. In that situation, an increase in the number of substrates has led to an increase in the factors that cause variations in the firing power. However, in the method of the present invention, as described above, when the deposition of the deposited film is started, the variation in the electric power for starting the discharge is substantially eliminated.
In essence, it has no effect, but rather is very effective from a productivity perspective.

The method of forming a deposited film of the present invention is particularly effective when a photoreceptor for electrophotography is prepared as a light receiving member. Electrophotographic photoconductors need to be thicker than, for example, photovoltaic devices. For this reason, film peeling is likely to occur from each part in the reaction container. Therefore, a method effective for suppressing film peeling, such as the method for forming a deposited film of the present invention, is very effective.

In order to achieve the object of the present invention and to form a deposited film having desired film characteristics, the gas pressure in the reaction vessel, the discharge power and the substrate temperature are determined by the type of the film to be deposited, the layer structure of the deposited film. It is necessary to set appropriately according to.

The optimum range of the gas pressure in the reaction vessel is appropriately selected according to the kind of the film to be deposited and the layer design.
Usually, at least within the range of 1.33 × 10 ^{−2 to} 1330 Pa, preferably 6.65 × 10 ^{−2 to} 665 Pa, particularly 1.33 × 10 ^{−1 to} 133 Pa. preferable.

Similarly, the optimum range of the discharge power is appropriately selected according to the type of the film to be deposited and the layer design.
For example, when depositing a-Si (H, X), the discharge power (W) with respect to the flow rate (ml / min (normal)) of the gas for supplying Si is usually 1 to 20 times, preferably 1 to 20 times. Is 2.5
It is desirable to set the range to 18 times, optimally 3 to 15 times.

Further, an optimum range of the temperature of the substrate is appropriately selected according to the kind of the film to be deposited and the layer design.
For example, when a-Si (H, X) is deposited, it is generally desirable to set the temperature to 200 to 350 ° C.

In the method of the present invention, the source gas is decomposed by applying high-frequency power to the high-frequency introducing means.
The frequency of the high-frequency power that can be used in the method of the present invention is not particularly limited. For example, when depositing a-Si (H, X), according to the experiments performed by the inventor, when the frequency is less than 50 MHz, In some cases, the discharge became unstable depending on the conditions, and the conditions for forming the deposited film were sometimes restricted. Further, variations in characteristics considered to be caused by unstable discharge occurred.
Further, for example, when the frequency is 13.56 MHz, it has been confirmed that the gas pressure in the reaction vessel where the plasma is stably discharged is approximately one digit higher than when the frequency is 50 MHz or more. At such a high gas pressure in the reaction vessel, particles such as polysilane are likely to be generated in the film forming space, and if these particles are taken into the deposited film, the film quality will be degraded. If the frequency is higher than 450 MHz, the transmission characteristics of high-frequency power deteriorate, and in some cases, it is sometimes difficult to generate glow discharge. In addition, non-uniform discharge occurs on the side opposite to the power introduction side, which is considered to be due to the deterioration of the transmission characteristics, and as a result, temperature unevenness occurs,
It becomes difficult to control the temperature of each component in the reactor. Therefore, in the frequency range of 50 MHz to 450 MHz, the method of the present invention can be more effectively performed.

The high-frequency waveform may be any waveform as long as power can be effectively introduced.
A commonly used sine wave, rectangular wave or the like is suitable.

In the method of the present invention, for example, a-Si
When (H, X) is deposited, the above-mentioned ranges are mentioned as desirable numerical ranges of the substrate temperature and the gas pressure for forming the deposited film, and these conditions are usually determined independently. However, in order to form an electrophotographic photoreceptor having desired characteristics, it is desirable to determine an optimum value based on mutual and organic relationships.

[0111]

EXAMPLES Hereinafter, the method for forming a deposited film of the present invention will be described in more detail with reference to examples, but the present invention is not limited to these specific examples.

(Example 1) Using the deposition film forming apparatus shown in FIG. 1, under the conditions shown in Table 1, the length was 358 mm and the outer diameter was 80 m.
Mirror-finished Al cylinder (cylindrical substrate)
A-Si deposition was performed thereon. At that time, the cylindrical substrate 1112
And the change in the surface temperature of the high frequency introducing means (cathode electrode 1116) were measured. In this experimental example, the frequency of the high-frequency power was 105 MHz. Note that the switching between the heating gas and the deposited film forming gas is performed as shown in FIG.
(A) was adopted, and the time of the gas replacement step was set to 10 minutes. The substrate temperature in the substrate preheating step was adjusted to 250 to 253 ° C. immediately before the gas replacement. The temperature was measured by bringing a thermocouple into contact with the surface of each part.

(Example 2) Using the deposited film forming apparatus shown in FIG.
A-Si deposition was performed on a mirror-finished Al cylinder (cylindrical substrate) having an outer diameter of φ80 mm. At that time, the change in the surface temperature of the cylindrical substrate 1112 and the change in the surface temperature of the high-frequency introducing means (cathode electrode 1116) were measured. The conditions other than those shown in Table 1 were the same as those in Example 1. However, in the present embodiment, the substrate cooling means 1114 was driven from the start of switching between the heating gas and the deposited film forming gas (at the start of the gas replacement step). He was used as a cooling gas.

(Comparative Example 1) Using the deposited film forming apparatus shown in FIG. 1 and employing the conditions shown in Table 1 except that the introduction of high-frequency power was interrupted at the time of gas switching, the length was 358 mm and the outer diameter was φ
A-Si deposition was performed on an Al cylinder (cylindrical substrate) having a mirror finish of 80 mm. At that time, the cylindrical substrate 1
The change in the surface temperature of 112 and the change in the surface temperature of the high-frequency introducing means (cathode electrode 1116) were measured. The conditions other than those shown in Table 1 were the same as in Example 1. That is, in this comparative example, the high-frequency power was once turned off at the end of the substrate preheating step, and the plasma was turned off at the time of switching between the heating gas and the deposited film forming gas. Then, at the start of the deposition film formation, high frequency power was again introduced to generate plasma.

FIG. 5 also shows the results obtained in Examples 1 and 2 and Comparative Example 1, that is, the results of measuring the temperature change from the substrate preheating step to the start of deposition film formation. As is clear from the results shown in FIG. 5, as compared with Comparative Example 1, as in Example 1 or Example 2, the heating gas and the source gas for forming the deposited film were replaced while the plasma was generated. By performing the deposition film formation, it is possible to suppress the temperature change of the support and the temperature change of the components in the reaction space during the transition from the heating to the deposition film formation. further,
Comparing Example 1 with Example 2, the temperature change of the base can be further suppressed by using the cooling of the base from the inner surface of the base.

[0116]

[Table 1] (Embodiment 3) Using the deposition film apparatus shown in FIG.
A 5-cycle electrophotographic photoreceptor was produced on an Al cylinder (cylindrical substrate) having a mirror surface of 8 mm and an outer diameter of 80 mm under the conditions shown in Table 2 according to the means of Example 1 described above. Also in the present embodiment, the plasma is maintained by supplying high frequency power when the gas for heating and the gas for forming the deposited film are exchanged. The frequency of the high frequency power is 105
MHz was used. In addition, the pattern of FIG. 2A is used for exchanging the heating gas and the deposition film forming gas (in this embodiment, the film formation condition of the charge injection blocking layer), and the time of the gas exchanging step is 10 minutes. And The substrate temperature in the substrate preheating step was adjusted to 250 to 253 ° C. immediately before the gas replacement.

Example 4 An electrophotographic photoreceptor was manufactured under the same conditions as in Example 3 using the deposited film apparatus shown in FIG. Also in the present embodiment, the plasma is maintained by supplying high frequency power when the gas for heating and the gas for forming the deposited film are exchanged. The frequency of the high frequency power is 105M
Hz was used. However, the switching between the heating gas and the deposition film forming gas (in this embodiment, the film formation conditions of the charge injection blocking layer) employs the pattern of FIG. 2B, and the time of the gas replacement step is 10 minutes. did. The substrate temperature in the substrate preheating step was adjusted to 250 to 253 ° C. immediately before the gas replacement.

Example 5 An electrophotographic photoreceptor was manufactured using the deposition film apparatus shown in FIG. 1 under the same conditions as in Example 3. However, in the present embodiment, the substrate cooling means 1114 was driven from the means employed in the second embodiment, that is, from the start of switching between the heating gas and the deposited film forming gas (at the start of the gas replacement step). He was used as a cooling gas. Even when the heating gas and the deposition film forming gas are exchanged, the plasma is maintained by supplying high-frequency power. The frequency of the high frequency power was 105 MHz. However, the exchange of the gas for heating and the gas for forming the deposited film (in this embodiment, the film formation conditions of the charge injection preventing layer) are performed as shown in FIG.
The pattern of (B) was adopted, and the time of the gas replacement step was 10 minutes.

Comparative Example 2 Using the deposited film apparatus shown in FIG. 1, a comparative example 1 was placed on a mirror-finished Al cylinder (cylindrical substrate) having a length of 358 mm and an outer diameter of φ80 mm.
A 5-cycle electrophotographic photoreceptor was produced under the conditions shown in Table 2 in accordance with the above procedure. That is, in this comparative example, when the gas for heating and the gas for forming a deposited film are exchanged, the high-frequency power is not supplied and the plasma is turned off. The frequency of the high frequency power was 105 MHz. In addition, the pattern of FIG. 2A is used for the exchange of the heating gas and the deposition film forming gas (in this embodiment, the film formation conditions of the charge injection blocking layer), and the time of the gas replacement step is 10 minutes. did.

With respect to the electrophotographic photoreceptors prepared in Examples 3, 4 and 5, and Comparative Example 2,
The following evaluations were performed, and the characteristics of the deposited films were compared.

[Charging Ability] [Characteristic Variation] An electrophotographic photoreceptor was mounted on an electrophotographic apparatus (Canon NP67).
50 was modified into a high-speed machine and used as a test device), a current of 800 μA was passed through the charger, corona charging was performed, and the surface potential of the dark portion of the electrophotographic photosensitive member was measured with a surface voltmeter. The formation of the deposited film is repeated for 5 cycles, and the average of the measured values for the sample in the 5 cycles is defined as the charging ability. In addition, the difference between the maximum value and the minimum value in the measured values for the sample in five cycles is defined as the variation in the charging ability.

"Number of spherical projections""Variation in number of spherical projections" The entire surface of the electrophotographic photosensitive member was observed with an optical microscope, and
The number of spherical projections having a diameter of 15 μm or more in an area of 0 cm ² was examined. The formation of the deposited film is repeated for 5 cycles.
The average of the measured values for the sample in the cycle is defined as the number of spherical projections. In addition, the difference between the maximum value and the minimum value in the measured values for the sample in five cycles is defined as the variation in the number of spherical projections.

[White Potty] A full black chart made by Canon (part number FY9-9073) is placed on a document table, and a copy image obtained when copying is examined in detail. The number in the same plane was counted. The formation of the deposited film is repeated for 5 cycles, and the average of the measured values for the sample for the 5 cycles is defined as white spots.

Further, the fluctuation of the high frequency power at the start of the formation of the charge injection blocking layer was observed. In "Comparative Example 2", the discharge starting power at the start of the charge injection blocking layer film formation was measured, and the difference between the maximum time and the minimum time was measured.

On the other hand, in Experimental Examples 3, 4, and 5, high-frequency power was continuously introduced from the substrate preheating step without interruption. Therefore, there is substantially no fluctuation in the electric power at the start of discharge at the start of the formation of the charge injection blocking layer.

Table 3 also shows the results obtained for each of the above evaluation items. In Table 3, all evaluation items except for "fluctuation of high-frequency power at the start of film formation of the charge injection blocking layer" were subjected to relative evaluation with the measured value (evaluation value) for the sample prepared in Comparative Example 2 as 100. Was.

The results shown in Table 3, ie, the results of Comparative Example 2 by the conventional method and the results of Examples 3, 4 and 5, are clearly shown. It was found that the use of the method for forming a deposited film significantly improved the chargeability and electrophotographic properties such as white spots. Furthermore, it was found that the variation was greatly reduced, and the reproducibility was greatly improved.

Further, when the results of Examples 3, 4 and 5 are compared in detail, good electrophotographic characteristics are obtained in all cases. It was found to be more favorable due to the improvement of the characteristics.

[0129]

[Table 2]

[0130]

[Table 3] Example 6 An electrophotographic photoreceptor was manufactured using the apparatus shown in FIG. 1 under the same conditions as in Experimental Example 3, and was evaluated for variations in charging capability and variations in the number of spherical projections. In this embodiment, the frequency of the high-frequency power source is set to 40M.
Hz to 500 MHz, and the comparison was performed. Table 4 shows the evaluation results obtained at the frequencies of the respective high-frequency power supplies in comparison.

From the comparison results shown in Table 4, when the frequency of the high frequency power supply is between 40 MHz and 500 MHz, there is a significant improvement over the conventional method. In particular, when the frequency of the high frequency power supply is selected in the range of 50 to 450 MHz, A remarkable reduction has been observed in both the variation in the charging ability and the variation in the number of spherical projections. That is, in the method of the present invention, when the frequency of the high frequency power supply is selected in the range of 50 to 450 MHz,
A result was obtained in which the effect of improving the reproducibility was even more remarkable.

[0132]

[Table 4] Example 7 An electrophotographic photoreceptor was manufactured using the apparatus shown in FIG. 1 under the same conditions as in Experimental Example 5, and was evaluated in the same manner as in Example 5. However, in this example, the temperature of the substrate was changed when the gas for heating and the gas for forming a deposited film were switched. That is, a temperature difference of the substrate was intentionally provided between the substrate preheating step and the deposited film forming step. That is, at the start of deposition film formation, stress distortion due to temperature change was intentionally applied to the deposition film, and the effects thereof were compared. Table 5 compares the results obtained when various temperature differences were provided.

From the results shown in Table 5, when the method of the present invention is used as compared with the conventional method, for example, the temperature difference of the substrate is reduced by 4%.
Even when the temperature is set to 9 ° C., there is a significant effect, specifically, an improvement in charging ability has been observed. Further, when compared in detail, even better results were obtained in the range where the temperature difference between the substrates was | 30 | (° C.) or less.

[0134]

[Table 5] (Embodiment 7) Using the deposition film apparatus shown in FIG.
Five cycles of the electrophotographic photoreceptor were produced under the conditions shown in Table 6 on a mirror-finished Al cylinder (cylindrical support) having a diameter of 8 mm and an outer diameter of 80 mm.

In the deposition film apparatus shown in FIG. 3, in this example, a cylinder made of alumina ceramics having an inner diameter of 240 mm, a thickness of 5 mm, and a surface property (Rz) of 30 μm was used as the reaction region separation vessel 3400. Cathode electrode 1116
A stainless steel round bar having a diameter of 10 mm was used, and the frequency of the high-frequency power was 105 MHz. Also in this embodiment,
When the gas for heating and the gas for forming a deposited film are exchanged, the plasma is maintained by supplying high-frequency power. In addition, the pattern of FIG. 2A is used for exchanging the heating gas and the deposition film forming gas (in this embodiment, the film formation condition of the charge injection blocking layer), and the time of the gas exchanging step is 10 seconds. did. The substrate temperature in the substrate preheating step was adjusted to 250 to 253 ° C. immediately before the gas replacement.

(Comparative Example 3) Using the deposited film apparatus shown in FIG. 3, a mirror-finished Al cylinder (cylindrical substrate) having a length of 358 mm and an outer diameter of 80 mm was placed in accordance with the means of Comparative Example 1 described above. Under the conditions shown in Table 6, 5 electrophotographic photosensitive members were produced. That is, in this comparative example, when the heating gas and the deposition film forming gas are exchanged, the plasma is turned off without supplying high frequency power. The frequency of the high frequency power was 105 MHz. In addition, the pattern of FIG. 2A is used for exchanging the heating gas and the deposition film forming gas (in this embodiment, the film formation condition of the charge injection blocking layer), and the time of the gas exchanging step is 10 seconds. did.

For the electrophotographic photosensitive members prepared in Example 7 and Comparative Example 3, the following “charging ability”, “variation in charging ability”, “number of spherical projections”, “spherical projections” Each item of "variation in numbers" and "white spots" was evaluated.

Table 7 also shows the results obtained for the above evaluation items. Table 7 shows the results of the relative evaluation, where the measured value (evaluation value) of the sample prepared in Comparative Example 3 by the conventional method was 100.

From the results shown in Table 7, the conventional method was applied as in Comparative Example 3 when using a deposition apparatus employing a reaction region separation container made of a dielectric material as shown in FIG. Compared to the case, as shown in Example 7, the use of the method of forming a deposited film of the present invention has significantly improved the electrophotographic properties such as charging ability and white spots, and their reproducibility. Was.

[0140]

[Table 6]

[0141]

[Table 7] (Embodiment 8) Using the light receiving member manufacturing apparatus shown in FIG.
A substrate was mounted on all of the substrate holders, and a plurality of cylindrical supports were formed on a mirror-finished Al cylinder (cylindrical substrate) having a length of 358 mm and an outer diameter of φ30 mm under the conditions shown in Table 8 under a condition shown in Table 8. An electrophotographic photoreceptor was manufactured at the same time, and a total of 5 cycles were manufactured. In the deposition film apparatus shown in FIG. 4, in this example, the reaction region separation container 4400 has an inner diameter of 350 mm, a thickness of 3 mm, and an inner surface property (Rz) of 30 μm.
m of alumina ceramics was used. Cathode electrode 41 arranged outside reaction region separation vessel 4400
For No. 16, a stainless steel round bar having a diameter of 20 mm was used. The reaction vessel 4111 itself is made of Al,
The frequency of the high frequency power was 105 MHz. Also in the present embodiment, the plasma is maintained by supplying high frequency power when the gas for heating and the gas for forming the deposited film are exchanged. In addition, the pattern of FIG. 2B is used for exchanging the heating gas and the deposition film forming gas (in this embodiment, the film formation condition of the charge injection blocking layer), and the time of the gas exchanging step is 30 minutes. did. The substrate temperature in the substrate preheating step is
Immediately before gas replacement, the temperature was set to 270 to 274 ° C. In addition to the switching between the heating gas and the deposition film forming gas, the high-frequency power to be introduced and the internal pressure in the reaction region separation vessel during the gas switching step are gradually increased as shown in FIG. Was changed to. further,
The substrate cooling means 4114 was driven from the start of switching between the heating gas and the deposition film forming gas (at the start of the gas replacement step). H ₂ was used as a cooling gas.

The prepared electrophotographic photosensitive member was evaluated for the following items: charging ability, charging ability variation, number of spherical projections, variation in the number of spherical projections, and white spots.

The evaluation results were the same as in Example 7 using the apparatus shown in FIG. 3, and good results were obtained for all the evaluation items. That is, as in the apparatus shown in FIG. 4, even when a plurality of substrates are arranged in the apparatus and a deposited film is formed at the same time, by applying the method of the present invention, both the deposited film characteristics and the reproducibility can be improved. The effect of improving is obtained.

"Charging Ability""Variation in Charging Ability" An electrophotographic photoreceptor was mounted on an electrophotographic apparatus (Canon NP6).
030 modified to a high-speed machine and used as a test device)
, And a current of 800 μA is passed through the charger to perform corona charging, and the surface potential of the dark portion of the electrophotographic light-receiving member is measured by a surface electrometer. The formation of the deposited film is repeated for 5 cycles, and the average of the measured values for all the samples manufactured in the 5 cycles is defined as the charging ability. In addition, the difference between the maximum value and the minimum value of the measured values for all the samples in a total of five cycles is defined as the variation in the charging ability.

"Number of spherical projections""Variation in number of spherical projections" The entire surface of the electrophotographic photosensitive member was observed with an optical microscope, and
The number of spherical projections having a diameter of 15 μm or more in an area of 0 cm ² was examined. The formation of the deposited film is repeated for 5 cycles.
The average of the measured values for all the samples produced in the cycle is defined as the number of spherical projections. In addition, the difference between the maximum value and the minimum value in the measured values for all the samples in a total of five cycles is defined as the variation in the number of spherical projections.

[White Potty] A full black chart made by Canon (part number FY9-9073) is placed on a platen, and a copy image obtained when copying is examined in detail. The number in the same plane was counted. The formation of the deposited film is repeated for 5 cycles, and the average of the measured values for all the samples manufactured in the 5 cycles is defined as the white spot.

[0147]

[Table 8]

[0148]

As described above, according to the method for forming a deposited film of the present invention, the characteristics of the deposited film are improved, the variation in the deposited film characteristics between substrates in the same lot and between lots is suppressed, and the uniformity is improved. -High reproducibility and stable deposition film formation.

Along with these effects and advantages, it is possible to stably produce semiconductor devices and electrophotographic photosensitive members having excellent characteristics at low cost.

[Brief description of the drawings]

FIG. 1 shows a conventional deposition film forming apparatus using a PCVD method.
It is the schematic which shows an example, (A) is a longitudinal cross-sectional view which shows the arrangement | positioning in a reaction container, (B) is a cross-sectional view which shows the member arrange | positioned in a reaction container, and is installed outside a reaction container. FIG. 2 is a diagram schematically showing various attached devices to be used.

2 (A) to 2 (C) are patterns of a change in a substrate heating gas flow rate (indicated by a dashed line) and a deposition film forming raw material gas flow rate (indicated by a solid line) in a gas replacement step in the deposited film forming method of the present invention. (D)
FIG. 4 is a diagram schematically showing the settings of the internal pressure in the reaction vessel (shown by a broken line) and the introduced high-frequency power (shown by a solid line) in a gas replacement step.

FIG. 3 is a schematic view showing one example of a deposited film forming apparatus by a PCVD method suitable for the deposited film forming method of the present invention, and FIG.
FIG. 3 is a longitudinal sectional view showing a relative arrangement of a reaction region separation vessel installed in the reaction vessel, and FIG. 2 (B) is a cross sectional view showing members arranged in the reaction vessel, and various kinds of components installed outside the reaction vessel. It is a figure which shows an attached device typically.

FIG. 4 is a schematic diagram showing one example of a deposited film forming apparatus by a PCVD method suitable for the deposited film forming method of the present invention, and FIG.
FIG. 3 is a longitudinal sectional view showing a relative arrangement of a reaction region separation vessel installed in the reaction vessel, and FIG. 2 (B) is a cross sectional view showing members arranged in the reaction vessel, and various kinds of components installed outside the reaction vessel. It is a figure which shows an attached device typically.

FIG. 5 shows the results of measurement of the substrate temperature (support temperature) before and after the gas replacement step in the method of the present invention, and the results of measurement of the substrate temperature (support temperature) before and after the start of deposition film formation by the conventional method. The figure below compares the measurement results of the cathode electrode temperature before and after the gas replacement step of the method of the present invention with the measurement results of the cathode electrode temperature before and after the start of the deposition film formation according to the conventional method. .

[Explanation of symbols]

1111, 3111, 4111 Reaction vessel (vacuum vessel) 3400, 4400 Reaction area separation vessel 1112, 3112, 4112 Cylindrical substrate 1113, 3113, 4113 Substrate holder 1114, 4114 Substrate cooling means 1115, 3115, 4115 Gas introduction pipe 1116, 3116 , 4116 Cathode electrode (high frequency introduction means) 1117, 3117, 4117 High frequency power supply 1118, 3118, 4118 Matching box 1122, 3122, 4122 Rotation axis 1120, 3122, 4122 Rotation drive mechanism (motor) 1100, 3100, 4100 Deposition device 1200, 3200, 4200 Supply device for source gas, etc. 1300, 3300, 4300 Exhaust device (for depressurizing the reaction vessel)

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hitoshi Hosoi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Hitoshi Murayama 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon (72) Inventor Daisuke Tazawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Kazutaka Akiyama 3-30-2, Shimomaruko 3-chome, Ota-ku, Tokyo Canon Inc. ( 72) Inventor Tatsuyuki Aoike 3-30-2 Shimomaruko, Ota-ku, Tokyo F-term in Canon Inc. (reference) 2H068 DA23 EA02 EA24 EA30 EA32 EA35 EA36 4K030 AA06 AA17 AA20 BA30 BB12 CA02 CA16 DA06 EA03 FA01 FA14 JA10 JA11 JA18 KA05 KA22 KA23 LA17

Claims (13)

[Claims] In a reaction vessel that can be depressurized, a substrate is placed in the reaction vessel, and a high-frequency power used for decomposition of a deposition-film-forming material gas is introduced from a high-frequency power introduction unit while a deposition film-forming material is introduced. A method for forming a deposited film on the substrate by supplying a gas, comprising: introducing a substrate heating gas and high-frequency power into the reaction vessel prior to forming the deposited film on the substrate. Then, a plasma is generated in the reaction vessel, and the substrate is heated by the generated plasma to provide a substrate preheating step of setting the substrate temperature to a predetermined temperature. In order to maintain the plasma generated in the substrate, while the high-frequency power is continuously introduced, the flow rate of the substrate-heating gas is gradually reduced, and the flow rate of the deposition-film-forming source gas is gradually increased. A gas exchange step of exchanging the deposition gas and the source gas for depositing film formation, and continuing the heating of the substrate by plasma, at the end of the gas exchanging step, setting the flow rate of the source gas for depositing film formation to a predetermined amount. And continuously forming a deposited film on the substrate without interrupting the introduction of high-frequency power. 2. The method according to claim 1, wherein the substrate heating gas is selected from He and H ₂ . 3. In the gas replacement step, in the replacement of the substrate heating gas and the deposition film forming source gas, the change in the flow rate of the substrate heating gas and the change in the flow rate of the deposition film formation source gas are simultaneously completed. 2. The method according to claim 1, wherein
Or the method for forming a deposited film according to 2. 4. In the gas replacement step, the replacement of the substrate heating gas and the deposition film forming source gas is performed before the end of the change in the flow rate of the deposition film formation source gas. The method according to claim 1, wherein the change is completed. 5. At least before the completion of the gas replacement step, the substrate is heated by the plasma on the outer surface, and the substrate is cooled from the inner surface of the substrate that is not directly heated by the plasma. The method for forming a deposited film according to claim 1. 6. The method according to claim 5, wherein the cooling of the base is performed by a direct heat conduction method. 7. The deposited film forming method according to claim 5, wherein the cooling of the base is performed at least at the time of starting the gas replacement step. 8. The deposition film forming method according to claim 1, wherein a change in substrate temperature during the gas replacement step is | 30 | ° C. or less. 9. The time required for the gas replacement step is as follows:
The method for forming a deposited film according to any one of claims 1 to 8, wherein the method is selected from a range of 10 seconds to 30 minutes. 10. The frequency of the high-frequency power is 50 MHz.
The method for forming a deposited film according to claim 1, wherein the frequency is selected in a range of z to 450 MHz. 11. The method according to claim 1, wherein the deposition film deposited on the substrate is for forming a photoconductor for electrophotography. 12. A reaction region separation container made of a dielectric member is provided in the reaction container, a high-frequency wave introducing means is provided outside the reaction region separation container, and the base is arranged inside the reaction region separation container. In addition, the supply of the substrate heating gas and the source gas for forming the deposited film is performed inside the reaction region separation container, and high-frequency power is supplied from the high-frequency introduction unit to generate plasma inside the reaction region separation container. The method for forming a deposited film according to claim 1, wherein the method is performed. 13. The deposited film according to claim 1, wherein a plurality of substrates are arranged in the reaction vessel, and a deposited film is formed on at least two or more substrates at the same time. Forming method.