JPS63266073A - Microwave plasma cvd device - Google Patents

Abstract

PURPOSE:To stably form a uniform and good-quality deposited film with excellent reproducibility by providing plural oil diffusion pumps as the exhaust means of the title microwave plasma CVD device. CONSTITUTION:Plural carriers 105, 305, and 402 for forming a deposited film are provided in the CVD device, and plural oil diffusion pumps DP are provided in the vicinity of the carriers as the exhaust means for the reaction vessels 101 and 301 having a decomposition space 106 wherein a raw gas such as silane is excited by the microwave energy and dissociated. As a result, the flow of the raw gas injected from gas discharge pipes 108 and 401 is uniformized as shown by the curved arrow, and the density of the gas in the space 106 is also uniformized. In addition, even if the remaining impurities are generated after the deposited film is formed several times, the possibility of the impurities remaining in the space 106 is remarkably reduced by the exhaustion from both sides. Accordingly, a good-quality deposited film having uniform thickness and quality can be formed on the carriers 105, 305, and 402 with excellent reproducibility.

Description

Detailed Description of the Invention (Technical Field to Which the Invention Pertains) The present invention relates to a film deposited on a substrate, particularly a functional film, particularly a semiconductor device, a photoreceptor device for electrophotography, a line sensor for image input, an imaging device, an optical The present invention relates to an apparatus for forming an amorphous semiconductor film used in an electromotive force device and the like, and a microwave plasma CVD apparatus such as an etching apparatus.

[Description of prior art]

Conventionally, amorphous silicon, such as hydrogen or/and Halogens (e.g. fluorine, chlorine, etc.)
compensated by amorphous silicon (hereinafter (a-3i(
Deposited films of amorphous semiconductors such as H;

Then, such a deposited film is deposited using a plasma CVD method, that is,
It can be formed by a method in which a raw material gas is decomposed by direct current, high frequency, or microwave glow discharge, and a thin film-like deposited film is formed on a support such as glass, quartz, heat-resistant synthetic resin film, stainless steel, or aluminum. This is known, and various devices for this purpose have been proposed.

Especially in recent years, plasma C using microwave glow discharge decomposition
The VD method is also attracting attention from an industrial perspective.

Such a conventional deposited film forming apparatus using the microwave plasma CVD method is typically shown in the schematic perspective view of FIG.
The apparatus shown in plan view is of the configuration tS.

In Figures 9 and 10, 901.1001 is a reaction vessel, and 6902.1 has a vacuum-tight structure.
002 is a dielectric window made of a material (for example, quartz glass, alumina ceramics, etc.) that can efficiently transmit microwave power into the reaction vessel and maintain vacuum tightness. 903°1003 is a microwave transmission section,
It mainly consists of a metallic rectangular waveguide, and has a matching box,
It is connected to a microwave power source (not shown) via an iso radar. 904.1004 is an exhaust port that opens into the vacuum vessel 901.1001 at one end and communicates with an exhaust device (not shown) at the other end.

905.1005 is a support on which a deposited film is to be formed, and 906.1006 represents a discharge space surrounded by the support.

Formation of a deposited film using such a conventional deposited film forming apparatus is performed in the following manner. First, a vacuum pump (not shown) connects the vacuum container 901.
1001 was degassed and the pressure inside the reaction vessel was reduced to I x 10-'
Adjust to below Torr. Next, the heater 907.1 (107) for heating the support body 905.1005
The temperature is maintained at a temperature suitable for film deposition. Therefore, when forming an amorphous silicon deposited film by passing the raw material gas through the gas discharge pipe 908.1008, for example,
A raw material gas such as silane gas or hydrogen gas is introduced into the reaction vessel. At the same time, a microwave power source (not shown) is used to generate a frequency of 500 MH! Above, preferably 2.
A microwave of 450H2 is generated, and this microwave passes through the waveguide 903.1003 and passes through the dielectric window 902.10.
02 into reaction volume 8901.1001. Thus, the gas in the reaction vessel 901.1001 is excited by the microwave energy, dissociates, and deposits on the support surface. At this time, by rotating the support, a deposited film is formed over the entire circumference of the support.

However, in such conventional devices, the introduced raw material gas is exhausted from one side, so the gas density becomes uneven between the discharge space near the exhaust port and the discharge space far away, making it difficult to obtain a stable discharge. Therefore, it has been difficult to normally form a deposited film of uniform thickness and quality.

[Purpose of the invention]

The purpose of the present invention is to
When forming a deposited film as an element member used in semiconductor devices, electrophotographic photoreceptor devices, photovoltaic devices, various other electronic devices, optical devices, etc., uniform, high-quality, and highly reproducible deposition is required. The object of the present invention is to provide a method for stably forming a film, and an apparatus most suitable for carrying out the method.

C Structure of the Invention] In order to achieve the above object, the present invention provides a microwave plasma having a support for forming a deposited film and a space for decomposing a raw material gas for forming a deposited film using microwave energy in the vicinity of the support. The CVD apparatus is characterized in that its exhaust means includes a plurality of oil diffusion pumps.

Hereinafter, the present invention will be explained in more detail with reference to specific examples, but the present invention is not limited thereto.

[Example] A specific example of a microwave plasma CVD apparatus that can achieve the object of the present invention is shown in a perspective schematic diagram in FIG. 1, a plan view in FIG. 2, and a cross-sectional diagram in FIG. 3.

In FIGS. 1, 2, and 3, 101°201.
301 is a reaction vessel, which has a vacuum-tight structure. 102, 202, and 302 are materials that can efficiently transmit microwave power into the reaction vessel and maintain vacuum tightness (for example, quartz glass, alumina ceramics, etc.)
It is a dielectric window made of. 103,203,303
is a microwave transmission section, which is mainly made of a metal rectangular waveguide, and is connected to a microwave power source (not shown) via a matching box and an isolator. 105,
205 and 305 are supports on which the deposited film is to be formed. 1
04, 204, 304, one end is the vacuum container 101, 20
1,301, and the other end is an exhaust device (not shown).
This is an exhaust port that communicates with the Support body 105, 205,
The temperature raising means and rotation mechanism 305, as well as the raw material gas introduction mechanism, have the same configuration as the microwave plasma CVD apparatus shown in FIGS. 9 and 10.

Microwave plasma CV of the present invention using the above-described mechanism
The operation of the D device will be explained in comparison with a conventional device. 1)
The figure shows a conventional device, and FIG. 4 shows the device of the present invention.
) figure and the arrow in figure 4 indicate the gas discharge pipe 1) 01.401
Figure 4, which shows the flow of the raw material gas ejected from the device of the present invention, shows the flow of the raw material gas that has been blown out.
It can be seen that the gas flow is uniform, and the gas density in the discharge space is also more uniform in FIG. 4 than in FIG. 1).

In addition, in this type of deposited film forming apparatus, the impurity substances shown in 1) Figure 3 remain after several times of deposited film formation, are generated as impurity gas by heating and discharge, and deteriorate the quality of the deposited film. It has been considered as one of the problems faced by
In the present invention shown in the figure, even if such impurities are generated, the possibility of them remaining in the discharge space is extremely small because they are exhausted from both sides.

As a result, the deposited film formed on the surface of each support 4020 has uniform thickness and quality, and is of good quality and highly reproducible. Note that, instead of arranging the exhaust ports facing each other as shown in FIGS. 1 to 3, they may be arranged at a certain angle as shown in FIGS. 5 and 6.

Hereinafter, an example in which a deposited film was formed using the microwave plasma CVD apparatus of the present invention will be described together with a comparative example in which a conventional apparatus was used. Note that the present invention is not limited to these examples.

■As shown in Figures 1, 2, 3, and 4, a microwave plasma CVD device with two oil diffusion pumps and raw material gas exhaust ports facing each other is used. As a cylinder made of AI with a length of 358mm and an outer diameter of 108φ.
A photosensitive drum consisting of a charge injection blocking layer, a photoconductive layer, and a surface protection layer was prepared on the support under the conditions shown in Table 1. Microwave power supply maximum 5Kw, 2.45GHz
A heating heater was used to heat the support using an oscillator, and the support was heated and maintained at a predetermined temperature while being rotated.

The following evaluation was performed on 120 photosensitive drums produced under such conditions.

(Evaluation A) Initial charging ability, sensitivity, residual Electrophotographic characteristics such as electric potential and ghost were checked, and a decrease in charging ability, surface abrasion, and increase in image defects after accelerated durability equivalent to 2 million sheets were also examined. Further, regarding film thickness, charging ability, and sensitivity, the following evaluations were also conducted at the same time.

(Evaluation B) Film thickness: Aj at which the deposited film was formed using an eddy current film thickness meter.
! Measure the film thickness in the center of the cylinder. The film thickness of each of the plurality of photosensitive drums produced in one film forming process is determined, and the average value of the film thicknesses is determined. The variation in film thickness of each photosensitive drum with respect to the average value is examined. By the above method, 20
Measurements were made for the film formation process.

Charging ability: The A1 cylinder on which the deposited film has been formed is mounted on a copying machine, and while the drum is being rotated, the surface potential at the center of the drum under a constant charging amount is measured. Determine the charging ability of each of the plurality of photosensitive drums produced in one film forming process,
The average value of the charging capacity is determined.

The variation in charging ability of each photosensitive drum with respect to the average value is examined. Using the above method, measurements were performed for 20 film forming steps.

Sensitivity: Charge in the same manner as above, and measure the surface potential after a certain amount of light exposure. The sensitivity of each of the plurality of photosensitive drums produced in one film forming process is determined, and the average value of the sensitivities is determined. The variation in sensitivity of each photosensitive drum with respect to the average value is examined. Using the above method, measurements were performed for 20 film forming steps.

The above comprehensive evaluation results are shown in Table 2.

As seen in Table 2, good results were obtained for all items.

Using a microwave plasma CVD apparatus with two oil diffusion pumps as shown in Figures 5, 6, and 7, and with the raw material gas exhaust port at a 90° position, the method shown in Example 1 was used. Similar experiments were conducted and similar evaluations were made. The results are shown in Table 3.

As shown in Table 3, good results were obtained for all items, but as compared to Example 1, there were slightly larger variations in film thickness, charging ability, and sensitivity.

Microwave plasma CVD shown in Figures 9 and 10
Using the same apparatus and under the film forming conditions shown in Table 4, experiments were conducted in the same manner as in Example 1, and the same evaluations were made. The results are shown in Table 5. As seen in Table 5, although good results were obtained for all items, there were large variations in film thickness, charging ability, and sensitivity compared to Example 1.

In the above embodiment, two oil diffusion pumps were used, but by using three or more oil diffusion pumps, the exhaust capacity is increased and film formation can be performed at a higher speed. Further, the shape and position of the raw material gas exhaust port is not limited to the above example. For example, by providing the exhaust port above and below the discharge space of the reactor, a deposited film with a more uniform film thickness and quality can be obtained. Furthermore, by using the apparatus shown in FIGS. 7 and 8, in which the exhaust port communicates with the reactor, it becomes possible to form a film of uniform thickness and quality at a higher speed.

[Summary of effects of the invention]

As explained above, according to the present invention, by having a plurality of oil diffusion pumps as exhaust means in a microwave plasma CVD apparatus, it is possible to form a deposited film at a higher speed, and furthermore, it is possible to form a deposited film at a higher speed. By selecting an appropriate shape, position, and number, a deposited film of better quality and uniformity can be formed, and a deposited film forming apparatus with high productivity and mass production can be provided.

Table 1 Table 3 ◎ - Particularly good 0... Good △... Practical soil Poor Table 4

[Brief explanation of drawings]

FIG. 1 is a perspective schematic diagram of an example of a deposited film apparatus using the microwave plasma CVD method according to the present invention, FIGS. 2 and 4 are plan views of FIG. 1, and FIG. 3 is a simplified diagram. FIGS. 5 and 7 also show microwave plasma C in the present invention.
It is a plan view of an example of a deposited film apparatus by the VD method, and FIGS. 6 and 8 are respective simplified diagrams. FIG. 9 is a schematic perspective view of a deposition apparatus using microwave plasma CVD method,
0 and 1) are plan views of FIG. 1. In the figure, 101,901.1001...Reaction vessel (reactor), 102,902.1002...Dielectric window, 103,903.1003...Waveguide, 104°9
04.1004...exhaust port, 105,402,905
゜1005...Support, 106,906.1006.
...Glow discharge plasma space (discharge space), 107°9
07.1007... Heating heater, 108.401
゜908.1008.1)01...Gas discharge pipe.

Claims (4)

[Claims] (1) In a microwave plasma CVD apparatus having a plurality of supports for forming a deposited film and a space for decomposing raw material gas for forming a deposited film using microwave energy in the vicinity of the supports, the exhaust means includes a plurality of oil A microwave plasma CVD apparatus characterized by having a diffusion pump. (2) The microwave plasma CVD according to claim 1, wherein the exhaust means includes two oil diffusion pumps.
Device. (3) The microwave plasma according to claim 1, wherein the exhaust means has an exhaust hole for the raw material gas introduced into the decomposition space, and the exhaust hole is the same as a side surface of the reactor. CVD equipment. (4) An exhaust hole for the raw material gas introduced into the decomposition space,
The microwave plasma CVD apparatus according to any one of claims 1 to 3, which is plural.