JPH062143A - Method of cleaning deposited film forming apparatus - Google Patents

Abstract

(57) [Summary] Improvement of a cleaning method of a deposited film forming apparatus by a CVD method using ClF ₃ gas. [Object] To provide a method for efficiently cleaning a deposited film forming apparatus by a CVD method. A cleaning method of a deposited film forming apparatus by a CVD method, in which ClF ₃ gas is used as a cleaning gas, the gas is mixed with a diluting gas, and the concentration is sequentially lowered to perform cleaning.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an efficient cleaning method in which damage to an exhaust device that occurs during cleaning of a device for forming a functional deposited film is prevented and the durability of the exhaust device is improved.

[0002]

2. Description of the Related Art An original reading device, a solid-state image pickup device in the image forming field, an electrophotographic image forming member, or a functional deposited film forming a photoelectric conversion layer in a solar cell or the like has high sensitivity and a SIN ratio ( High photocurrent [Ip] / dark current [Id]), having an absorption spectrum matching the spectral characteristics of the electromagnetic wave irradiated,
It is required to be harmless to the human body. Examples of such a functional deposited film include an amorphous silicon film (hereinafter referred to as “a-Si film”) and selenium (Se).
Examples thereof include a film and a CdS film. Then, these functional deposited films are formed by a film forming method such as a vacuum vapor deposition method, a sputtering method, a vapor phase chemical method or the like for forming a film under reduced pressure.

By the way, when a functional deposited film is formed on a predetermined substrate by these film forming methods, a deposited film or a powdery polymer (hereinafter simply referred to as "powder") is formed on a member for forming a film forming chamber or the like. Abbreviated) will be accumulated.
For example, when a film is formed by a gas phase chemical method by glow discharge decomposition, a deposited film or powder is formed on the inner wall of the reaction chamber (film forming chamber) other than the substrate such as the susceptor, the counter electrode, or the reaction furnace. It is formed. These deposited films or powders are impaired in the film formed during the next film formation as impurities to deteriorate the characteristics of the obtained film, or the powder adheres to the substrate to cause defects such as pinholes. It will bring to the resulting film. Then, when the film formation is repeated several times, the yield of the target deposited film is significantly reduced.

For this reason, after several film forming cycles or every film forming cycle, the film forming chamber is cleaned to remove the film deposited on the portion other than the intended deposited film forming location. As a cleaning method at that time, there is a method of dismantling the reaction container (film forming chamber) and mechanically removing the deposited film or powder. However, this method not only requires a great deal of labor for dismantling and assembling the reaction furnace each time, but at the time of dismantling, the inner wall of the reaction container is exposed to the atmosphere, and adsorption of water and the like occurs, which causes the film to be obtained. The characteristics of may deteriorate. Furthermore, when the deposited film or powder is exposed to the atmosphere, there is a risk of ignition or explosion depending on the type.

As a cleaning method for solving the above-mentioned problems, the elements forming the deposited film or the powder are reduced by gas phase molecules by a gas phase chemical reaction, and cleaning is performed.
A so-called dry etching cleaning method has been proposed. In the dry etching cleaning (hereinafter simply referred to as “cleaning”) method, for example, CF ₄ gas, N 2
A so-called etching gas such as F ₃ gas or SF ₆ gas is caused to flow in the reaction vessel and is excited by energy such as plasma, heat or light to react with an element forming a deposited film or powder, This is a method of cleaning by removing the element as a gas phase molecule and removing it by an exhaust means.

According to the dry etching method, it is not necessary to disassemble the reaction container for cleaning, and the inside of the reaction container can be cleaned in a closed system.

Recently, C has been used as a gas having an etching action.
Attention has been paid to IF ₃ gas. ClF ₃ gas decomposes with low energy and is highly reactive, and has an extremely high etching rate as compared with a conventional etching gas. For example, when etching an amorphous silicon (hereinafter abbreviated as a-Si) film, in the case of a conventional etching gas such as CF ₄ , NF ₃ , SF ₆ or the like, external energy such as plasma, heat, light, etc. is not applied. Then, the etching reaction does not proceed, whereas in the case of ClF ₃ gas, the etching proceeds only by the gas touching the a-Si film, and it is not necessary to supply energy from the outside.

When the ClF ₃ gas having the above properties is used as an etching gas for cleaning the reaction chamber, it is expected to shorten the time required for cleaning the reaction chamber. However, when ClF ₃ gas is actually used for cleaning the reaction chamber, the following problems occur.

That is, there is a problem of damage to the exhaust system due to ClF ₃ gas acting on the exhaust system including the exhaust pump. Specifically, ClF ₃ is added to the exhaust system.
By flowing the gas, for example, fluttering accompanied by abnormal noise is generated from the exhaust pump, or seizure occurs in the pump immediately before the end of cleaning, and in the worst case, the exhaust pump is damaged. Such a problem in flowing ClF ₃ gas is not a problem in the conventional cleaning method using CF ₄ , NF ₃ , SF ₆ gas or the like, and is extremely high in the reactivity of ClF ₃ gas. Seems to be involved.

In view of the above problems when using ClF ₃ gas, in actual use, the exhaust pump is stopped or the oil of the exhaust pump is changed after cleaning for a certain period of time. Etc. have been dealt with. However, according to this coping method, there are problems that the cleaning time is extended in proportion to the dwell time of the exhaust pump and the number of maintenance is increased.

As another countermeasure, when using ClF ₃ gas, there is a method of diluting it to a very low concentration with a diluent gas. However, in this case, the advantage of ClF ₃ gas that the cleaning speed is high cannot be fully utilized. That is, the ClF ₃ gas itself provides an etching rate several times higher than that of the conventional etching gas, but when used in a large amount when diluted,
The flow rate of the ClF ₃ gas itself is limited, and as a result, the time required for cleaning is almost the same as when using the conventional etching gas.

As described above, the above problems when using ClF ₃ gas as a cleaning gas are solved,
It is desired to provide a method of efficiently performing cleaning at high speed without damaging the exhaust system.

[0013]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a cleaning method for efficiently cleaning a deposited film manufacturing apparatus by overcoming the above-mentioned problems in the prior art when cleaning the deposited film manufacturing apparatus by a vapor phase chemical method. And

[0014]

The method of cleaning a deposited film manufacturing apparatus according to the present invention is a method of cleaning a deposited film manufacturing apparatus that forms a deposited film under reduced pressure by a vapor phase chemical method, and uses ClF ₃ gas as a cleaning gas. Is used as a mixture with a diluting gas, and cleaning is performed while the concentration of the ClF ₃ gas is gradually decreased.

As a result of various studies by the present inventors, the following has been found. That is, the damage to the exhaust system when ClF ₃ gas is caused to flow is mainly due to the fact that the oil that lubricates the moving parts of the exhaust system comes into contact with the ClF ₃ gas, and mainly carbon and hydrogen that make up the oil. This is because the linkage of the chain consisting of is instantly broken and the oil has a low molecular weight, and as a result, the viscosity of the oil is lowered and it becomes impossible to maintain the viscosity required as a lubricant. The decrease in oil viscosity is
The diluent gas is added to the ClF ₃ gas passing through the exhaust system, and Cl
It can be prevented by lowering the concentration of F ₃ gas. However, simply lowering the ClF ₃ concentration causes a new problem that the etching rate decreases and the tact time required for cleaning increases.

On the other hand, comparing the gas species at the start of etching when cleaning the reaction chamber and immediately before the end of etching, a large amount of the film or powder produced in the previous film deposition process is present in the reaction chamber at the start of etching. The ClF ₃ gas introduced into the reaction chamber at this point rapidly reacts with the residual substance. For example, if the residual substance is a substance containing Si, the reactivity of SiF ₄ etc. Most of the gas that becomes low gas and reaches the exhaust system has relatively little damage to the exhaust system, and the above-mentioned problems do not occur. On the other hand, a large amount of the residual substance in the reaction chamber has been already cleaned just before the end of etching, and most of the ClF ₃ gas introduced into the reaction chamber at this point is unreacted. It reaches the exhaust system as it is. As a result, the reaction with the oil in the exhaust system increases, and the above-mentioned problems occur.

Based on the above findings, the present inventors set the concentration of ClF ₃ gas to be introduced into the reaction chamber to a high concentration state at the start of etching, and gradually decrease it to a low concentration state at the end of etching, and after the reaction. By setting the concentration of ClF ₃ gas reaching the exhaust system to a certain value or less from the start to the end of etching, the above-mentioned problems are solved, and ClF 3
It has been found that cleaning can be performed by utilizing the high etching rate of ₃ gases. And this has a great effect if it is a moving part that uses oil as a lubricant in the exhaust system of the deposited film manufacturing apparatus, and especially in a rotary pump, a movable powder trap, etc. There was found.

In the cleaning method of the present invention, Cl
Examples of the diluent gas mixed with the F ₃ gas include an inert gas such as Ar, He, Ne. Also, ClF ₃
The gas is not particularly limited as long as it does not react when mixed with the gas, and for example, N ₂ , O ₂ or the like can be used. Still another etching gas such as CF
It is also possible to use it by mixing with ₄ , NF ₃ , SF _6, etc.

In the cleaning method of the present invention, it is desirable that the concentration of ClF ₃ gas supplied to the reaction furnace be sequentially changed from a maximum of 80% to a minimum of 5%. However, the use of ClF ₃ gas more than 80% strength, high ClF ₃ gas concentration to reach the exhaust system even when the deposit in the reaction chamber remains, a large damage to the exhaust system. On the other hand, when the concentration is 5% or less, the etching rate decreases, and the etching rate becomes the same as when the conventional etching gas is used, and the high etching rate, which is a feature of ClF ₃ gas, cannot be achieved.

In the cleaning method of the present invention, Cl
The method of changing the concentration when the F ₃ gas concentration is gradually decreased is not particularly limited, but at least 2
It is desirable that the ClF ₃ gas concentration be changed linearly or exponentially from the start of etching to the end of etching in a stepwise change of steps or more. 1 to 4 show patterns of changes in ClF ₃ concentration. FIG. 1 shows an example in which the ClF ₃ gas concentration is changed in two steps. Figure 2
This is an example in the case of changing in three stages. FIG. 3 shows an example in which the ClF ₃ concentration is linearly decreased from the start to the end of etching. FIG. 4 shows an example in which the ClF ₃ concentration is exponentially lowered.

In the cleaning method of the present invention, Cl
Although the F ₃ gas has an etching action when it is simply flowed,
For the purpose of controlling the etching rate, selecting active species, and the like, etching may be performed by supplying energy from outside such as heat, plasma, or light as necessary.

In the cleaning method of the present invention, the kind of the deposited film or powder to be cleaned is not particularly limited, and for example, silicon (Si), tungsten (W), titanium carbide (TiC), titanium nitride (Ti).
N), boron nitride (BN), ITO, or any other substance that has an etching action by ClF ₃ gas can exert the effects of the present invention.

According to the cleaning method for a deposited film manufacturing apparatus of the present invention having the above-described structure, ClF ₃ gas is used without damaging the exhaust system of the deposited film manufacturing apparatus or causing a decrease in performance. The deposited film manufacturing apparatus can be cleaned at an extremely high etching rate. Then, not only the cleaning time can be shortened and eventually the manufacturing cost of the deposited film can be reduced, but also the life of a device such as a rotary pump in the exhaust system can be significantly extended and the deterioration of oil can be prevented. As a result, it is possible to reduce the maintenance frequency.

[0024]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

Example 1 As an example of the present invention, an example of cleaning a deposited film forming apparatus when an a-Si type photoconductor for electrophotography is prepared by using an RF plasma CVD method will be described below. FIG. 5 is a schematic diagram of a deposited film forming apparatus used when forming an a-Si-based photoconductor for electrophotography by the RF plasma CVD method.

In FIG. 5, 201 is a reaction furnace, 202 is a cylindrical aluminum substrate, and 203 is a heater for heating the substrate, which can be heated to a desired temperature by a power source (not shown). Reference numeral 204 is a motor for rotating the substrate, which is used to make the film deposited on the substrate uniform in the circumferential direction. 205 is a vacuum gauge for knowing the pressure in the reaction furnace. Reference numeral 206 denotes an electrode for exciting RF glow discharge, which is supplied with electric power from a power source 207. Reference numeral 208 is a reactor leak valve, 209 is an exhaust pipe, 210 is an exhaust stop valve, 211 is an exhaust pump such as a mechanical booster pump whose exhaust speed is variable, 212
Is a rotary pump. 213 is a port provided with a glass plate for observing the inside of the furnace. Reference numeral 214 is a gas pipe for guiding the gas to the reaction furnace. 220, 230, 240, ..., 2
Reference numeral 90 is a gas-filled cylinder. 220 is S
iH ₄ gas cylinder, 230 is H ₂ gas cylinder, 240 is B
₂ H ₆ gas cylinder (3000 ppm, H ₂ diluted, hereafter “B ₂
Abbreviated as “H ₆ / H ₂ ”), 250 is a NO gas cylinder, 2
60 is a GeH ₄ gas cylinder, 270 is a CH ₄ gas cylinder,
280 is an Ar gas cylinder and 290 is a ClF ₃ liquefied gas cylinder. , 291 are cylinder open / close valves, 222, 232, ..., 292 are pressure reducers for adjusting gas pressures, 223, 233, ..., 293, respectively.
, 294 are mass flow controllers for adjusting gas flow rates, and 225, 235, ..., 295 are gas supply valves. 296 heats a ClF ₃ liquefied gas cylinder to generate C
It is a heater for vaporizing 1F ₃ gas.

First, a process of forming an a-Si type photosensitive member using the deposited film forming apparatus shown in FIG. 5 will be briefly described. First, a cylindrical aluminum substrate (length: 358 mm, diameter: 80) that has been subjected to predetermined processing, surface treatment, and cleaning.
mm, wall thickness 5 mm) is installed in the reaction furnace. Next, after opening the valve 210, the rotary pump 212 and the mechanical booster pump 211 are activated to start the reaction furnace 20.
The inside of 1 is decompressed. The pressure inside the reaction furnace 201 is measured by a vacuum gauge 20.
When the pressure becomes 0.001 Torr or less, the substrate is rotated at 1 rpm by the motor 204, and electric power is supplied to the heater 203 from a power source (not shown) to heat the substrate 202 to 300 ° C. .

When the temperature of the substrate 202 reaches 300 ° C.
And the a-Si-based photoreceptor on the substrate under the conditions shown in Table 1.
Long-wavelength absorption layer, charge injection blocking layer, photoconductivity
A layer and a surface protective layer are sequentially formed. Form long-wavelength light absorption layer
To do SiH _Four, H₂, B₂H₆/ H₂, NO, GeH_Four
Filled cylinder valves 221, 231, ..., 26
Open 1 and put each gas into the decompressor for each gas 222, 23
The pressure is reduced to a desired pressure by 2, ..., 262. Next introduction
Open the valves 223, 233, ...
Mass flow controllers 224, 234, ..., 26
Introduce to 4. Mass flow controller for each gas
Is controlled to a desired flow rate by the supply valves 225, 2
35, ..., 265, after which the gas pipe 214 is mixed.
Is introduced into the reactor.

The long wavelength light absorbing layer was formed under the conditions shown in Table 1. That is, SiH ₄ gas flow rate 100 sccm, H ₂
The gas flow rate is 600 sccm, and the B ₂ H ₆ / H ₂ gas flow rate is Si
3000 ppm against H ₄ gas flow rate, NO gas flow rate 5
The flow rate was adjusted by a mass flow controller so that the flow rate of the sccm and GeH ₄ gas was 50 sccm. Then vacuum gauge 20
While watching 5, the exhaust speed of the exhaust pump 211 was adjusted to adjust the pressure in the reaction furnace to 0.5 Torr. Next, by supplying electric power from the RF power source 207, glow discharge was caused between the electrodes 206 to start the formation of the long wavelength light absorption layer.
When the long wavelength light absorbing layer having a desired film thickness was formed, the discharge was stopped and the formation of the long wavelength light absorbing layer was completed. Thereafter, the charge injection blocking layer, the photoconductive layer, and the surface layer were sequentially formed under the conditions shown in Table 1 by the same procedure.

At the time of switching the formed layers, all valves were closed as needed, and the inside of the system was once evacuated to a high vacuum. When the formation of all layers constituting the a-Si photosensitive member is completed as described above, the heating power source is turned off,
The inside of the a-Si photosensitive member and the reaction furnace were cooled. The a-Si photosensitive member cooled to room temperature was taken out from the reaction furnace. This a-Si photoconductor is used as an electrophotographic device NP-9 manufactured by Canon.
When it was set at 330 and an image was taken out, an extremely clear image was obtained. On the other hand, the inner wall of the reaction furnace 201, the RF electrode 2
A large amount of film and powder were formed on the surface of 06 and the inner wall of the exhaust pipe 209 (hereinafter, these film and powder are abbreviated as “residual substances”).

The residual substance deposited in the reactor is cleaned with a cleaner.
Was performed. That is, ClF₃Gas concentration three steps
The cleaning method of the present invention was carried out by changing the floor. So
Cleaning conditions are shown in Table 2, and density change pattern
Is shown in FIG. The progress of cleaning is window 213
Visual inspection, exhaust pipe 209 and rotary pump
The temperature of 212 was monitored during cleaning. That is, the reactor
After confirming that the inside of 201 is vacuum,
In the same procedure, from cylinder 290 to ClF₃Gas
Ar gas was introduced into the reaction furnace from the chamber 280.
At this time, ClF ₃Liquefied gas cylinder 290 is heater 29
Heated by 6 to vaporize the required amount of gas
It was ClF₃Mass flow adjustment of gas and Ar gas
Controller 294 and 284 are used to control the pressure inside the reactor.
Force adjustment is performed by adjusting the mechanical booster pump 211.
It was.

The cleaning conditions for the first stage were as shown in Table 1. That is, the ClF ₃ gas concentration is 50% (Cl
F ₃ gas flow rate 1000 sccm, Ar gas flow rate 1000
sccm) and the reaction furnace internal pressure was 1 Torr for 20 minutes.
When the first stage cleaning is completed, the observation window 21
When the inside of the furnace was visually inspected through No. 3, the residual substance in the furnace was significantly reduced, and about 70% had already been cleaned. Next, ClF ₃ gas concentration 20% (Cl
F ₃ gas flow rate 400 sccm, Ar gas flow rate 1600 s
ccm) and the reactor internal pressure was 1 Torr, and the second stage cleaning was performed for 15 minutes. When the second stage cleaning was completed, about 90% of the residual substances were cleaned. Then, ClF ₃ gas concentration 10% (ClF ₃ gas flow rate 200 sccm, Ar gas flow rate 1800 sccm),
The internal pressure of the furnace was set to 1 Torr, and the third stage cleaning was started. After cleaning for 15 minutes, the residual substance in the reaction furnace was completely cleaned. During the cleaning, problems such as flapping of the exhaust pump and seizure in the pump did not occur.

FIG. 7 shows changes in the temperatures of the exhaust pipe and the rotary pump during cleaning. The temperature of the rotary pump was relatively stable during cleaning, although there was a rise of about 5 ° C. at the end of each cleaning step. The temperature of the exhaust pipe showed a slightly sharp rise at the end of cleaning.

During cleaning, the gas flowing through the exhaust pipe was sampled after 25 minutes and 50 minutes, and the components were analyzed by gas chromatography. As a result, ClF ₃ gas is about 1 in the gas after 25 minutes.
The gas content after 5 minutes was 5%, and about 10% was contained.

Further, conventionally, when ClF ₃ concentration was used at a constant high concentration, the valve plate used in the rotor of the rotary pump was corroded or the organic parts used in the pipes and joints were damaged. However, in the cleaning method of the present invention, corrosion and damage to these components were extremely small.

FIG. 8 shows changes in pressure during cleaning in the cleaning method of the present invention. The pressure is set to 1 Torr at the beginning of each stage during cleaning, and the pressure is not adjusted during each stage. As shown in FIG. 8, a slight pressure increase was observed at the end of the first and second cleaning steps, and a sharp pressure increase was observed at the end of the third and final cleaning step. From the above facts, it is possible to utilize for a simple detection of the end of cleaning, that is, a rise in pressure is found at the end of cleaning.

As described above, one cycle of forming the a-Si type photosensitive member and cleaning the inside of the reaction furnace is completed. This a-S
After the cycle of forming the i-type photosensitive member and cleaning the inside of the reaction furnace was performed 10 times, the oil used in the rotary pump was analyzed and the viscosity of the oil was reduced by about 5%.

Comparative Example 1 In this example, the conventional cleaning method was carried out without changing the ClF ₃ concentration. The a-Si-based photoreceptor was prepared in the same manner as in Example 1. The state of the residual substances inside the reaction furnace was the same as in the case of Example 1.

Cleaning of the inside of the reaction furnace was performed with a ClF ₃ gas concentration of 50% (ClF ₃ , 1000 sccm, Ar, 10
(00 sccm) The internal pressure of the furnace was 1 Torr. The changes in the temperature of the rotary pump and the exhaust pipe at that time are shown in FIG. After 20 minutes from the start of cleaning, the temperature of the rotary pump gradually increased. Flapping accompanied by abnormal noise was generated in the rotary pump from the time point when 23 minutes had elapsed. The temperature of the exhaust pipe increased sharply after 50 minutes. After 27 minutes, the exhaust capacity drops sharply,
The pressure inside the furnace increased accordingly. At this point, it was judged that cleaning could not be continued, and the flow of ClF ₃ gas and Ar gas into the reaction furnace was stopped. After the cleaning was stopped, when the inside of the reaction furnace was observed, residual substances were present in the reaction furnace.

As in Example 1, the gas flowing in the exhaust pipe was analyzed 15 minutes and 25 minutes after the start of cleaning. As a result, ClF ₃ gas was about 15% for 25 minutes after the lapse of 15 minutes. The gas after the passage contained about 50%. After 27 minutes of cleaning time, the pressure increased rapidly. This increase in pressure is caused by the deterioration of the exhaust capacity of the pump and cannot be used for detecting the end of cleaning.

When the oil of this rotary pump was analyzed, the viscosity of the oil was reduced by about 20%. Further, when the rotary pump was disassembled and the inside was examined, a discolored portion due to poor lubrication was found in the contact portion between the rotor and the bearing.

From the above, ClF is used during cleaning.
_{When 3} gas is supplied into the reaction furnace at a certain high concentration, a large amount of ClF ₃ gas flows unreacted into the exhaust system as cleaning progresses, resulting in low viscosity of oil and poor lubrication of moving parts. It was found that there was fluttering with abnormal noise.

COMPARATIVE EXAMPLE 2 In this example, the conventional cleaning method was performed without changing the ClF ₃ concentration. The a-Si-based photoreceptor was prepared in the same manner as in Example 1. The state of residual substances inside the reactor was the same as in Example 1. For cleaning, ClF ₃ gas concentration 10% (Cl
_{F 3, 200sccm, Ar, 1800sccm} ), was carried out in furnace pressure 1Torr conditions. The completion of cleaning was visually observed through the window, and judged by the disappearance of residual substances in the reaction furnace. As a result, 150 for cleaning
It took a minute. From the start to the end of cleaning, no abnormal noise of the rotary pump or deterioration of exhaust capacity was observed.
Figure 1 shows the temperature changes of the rotary pump and exhaust pipe at this time.
It was shown at 0.

From the above, under the cleaning conditions of this comparative example, the exhaust system was not damaged and
It is possible to complete the cleaning, but it took 150 minutes to complete the cleaning, and it was found that the advantage that the ClF ₃ gas had an extremely high etching rate could not be utilized. When the cycle of film deposition and cleaning was repeated, it was found that there was a problem in mass productivity.

Comparative Example 3 In this example, CF ₄ gas and O ₂ gas were mixed as a cleaning gas for cleaning. The a-Si-based photoreceptor was prepared in the same manner as in Example 1. The state of the residual substances inside the reaction furnace was the same as in the case of Example 1. Cleaning is CF ₄ , 1600scc
m, O ₂ , 400 sccm, furnace pressure 1 Torr, and discharge power 1 kW. Note that this condition is CF ₄
The conditions are optimized in the mixed system of gas and O ₂ gas. The completion of cleaning was visually observed through the window, and judged by the disappearance of residual substances in the reaction furnace. As a result, 170 minutes were required for cleaning. From the start to the end of cleaning, no abnormal noise of the rotary pump or deterioration of exhaust capacity was observed.

From the above, under the cleaning conditions of this comparative example, the exhaust system was not damaged and
It was possible to complete the cleaning, but it was found that it took 170 minutes to complete the cleaning.

Example 2 In this example, the cleaning method of the present invention was used in which the ClF ₃ concentration was exponentially gradually decreased from the start of cleaning to the end of cleaning. The a-Si photosensitive member was prepared in the same manner as in Example 1. The state of the residual substances inside the reaction furnace was the same as in the case of Example 1. For cleaning, the furnace pressure was set to 1 Torr, He gas was used as a dilution gas, and the ClF ₃ gas concentration was 80% at the start of cleaning to 50 at the end of cleaning.
% Was continuously changed. The change pattern is shown in FIG. After the lapse of 50 minutes from the start of cleaning, the residual substance in the reaction furnace was completely cleaned. Further, during cleaning, problems such as flapping of the exhaust pump and seizure in the pump did not occur.

[0048]

[Table 1]

[0049]

[Table 2]

[0050]

As described above, in the cleaning process by the vapor phase chemical method of the deposited film manufacturing apparatus for manufacturing a functional deposited film under reduced pressure, ClF ₃ gas is mixed as a cleaning gas with a diluent gas. By using and cleaning while gradually lowering the ClF ₃ gas concentration, the exhaust system of the deposited film manufacturing apparatus is damaged,
Alternatively, the deposited film production apparatus can be cleaned at an extremely high etching rate by using ClF ₃ gas without causing a decrease in performance. According to this cleaning method, not only the manufacturing cost can be reduced by shortening the cleaning time, but also the life of devices such as rotary pumps, valve materials of rotors, pipes, and joints in the exhaust system can be significantly extended, and oil can be further reduced. It is possible to reduce the maintenance frequency by preventing the deterioration of the above. As a side effect, the end of cleaning can be found by monitoring the change in cleaning pressure.

[Brief description of drawings]

FIG. 1 is a diagram showing a concentration change pattern when the concentration of ClF ₃ gas is sequentially reduced in two steps in the present invention.

FIG. 2 is a diagram showing a pattern of concentration change when the concentration of ClF ₃ gas is sequentially reduced in three steps in the present invention.

FIG. 3 is a diagram showing a pattern of concentration change when the concentration of ClF ₃ gas is linearly and sequentially changed from the start to the end of cleaning in the present invention.

FIG. 4 is a diagram showing a concentration change pattern when the concentration of ClF ₃ gas is exponentially changed from the start to the end of cleaning in the present invention.

FIG. 5: aS for electrophotography by RF plasma CVD method
FIG. 3 is a schematic diagram of a deposited film forming apparatus used when creating an i-type photoreceptor.

FIG. 6 shows a cleaning method according to the first embodiment of the present invention,
ClF ₃ is a graph showing changes in concentration of the gas.

FIG. 7 shows the cleaning method according to the first embodiment of the present invention,
It is a figure which shows the temperature change of an exhaust system.

FIG. 8 shows the cleaning method according to the first embodiment of the present invention.
It is a figure which shows the mode of pressure change.

FIG. 9 is a diagram showing a temperature change of an exhaust system in Comparative Example 1 which is a conventional cleaning method.

FIG. 10 is a diagram showing a temperature change of an exhaust system in Comparative Example 2 which is a conventional cleaning method.

FIG. 11 is a diagram showing changes in the concentration of ClF ₃ gas in Example 2 of the present invention.

[Explanation of symbols]

201 Reaction Furnace 202 Cylindrical Aluminum Substrate 203 Heater for Substrate Heating 204 Motor for Rotating Substrate 205 Vacuum Gauge 206 Electrode for Exciting RF Glow Discharge 207 RF Power Source 208 Reactor Leak Valve 209 Exhaust Pipe 210 Exhaust Stop valve 211 Exhaust pump such as mechanical booster pump whose exhaust speed is variable 212 Rotary pump 213 Port 214 provided with a glass plate 214 Gas pipes 220, 230, 240, ..., 290 Gas filled cylinders 221, 231 ,. 291 Open / close valves for each cylinder 222, 232, ..., 292 Pressure reducer 223, 233, ..., 293 Gas introduction valve 224, 234, ..., 294 Mass flow controller 225, 235, ..., 295 Gas supply valve 296 Heater

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Toshiyuki Ehara 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (1)

[Claims] 1. A cleaning method according to the gas phase chemistry of an apparatus for forming a deposited film under reduced pressure, using a ClF ₃ gas as cleaning gas is mixed with a diluent gas, of the ClF ₃ gas A method for cleaning a deposited film forming apparatus, characterized in that cleaning is performed while the concentration is sequentially reduced.