JPS6239532B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a film forming method that is effective for forming, for example, a photoconductive film, a semiconductor film, an inorganic insulating film, or an organic resin using discharge such as glow discharge. When trying to form a film with desired characteristics on a given support by decomposing a reaction gas for film formation using plasma phenomenon, especially in the case of a large-area film, the total area It is much more difficult to achieve uniform film thickness, uniform physical properties such as electrical, optical, photoelectric, etc., and uniform quality over the course of the process, compared to ordinary vacuum evaporation methods.

For example, when SiH ₄ gas is decomposed using discharge energy to form an amorphous silicon hydride (hereinafter referred to as a-Si:H) film on a support, and the electrical properties of this film are to be utilized. Since the electrical properties of this film are highly dependent on the discharge intensity during film formation, in order to obtain uniform electrical properties over the entire film region, it is necessary to equalize the discharge intensity throughout the film formation region. .

The uniformity of this discharge intensity depends on the electric field strength, gas flow rate, gas pressure, arrangement of gas introduction and discharge positions,
It mainly depends on factors such as the shape and arrangement of the discharge electrode.

However, with the film formation methods that have been proposed so far, it is not possible to uniquely determine the above factors and obtain a uniform discharge intensity that optimizes the film formation conditions. At present, film formation is performed under the following conditions.

In addition, in order to form a large-area film with good productivity and mass production, it is necessary to economize gas consumption so that as much gas as possible is consumed only for film formation, and to reduce the concentration of the reaction gas in the film formation area. To avoid uneven distribution, and to avoid requiring a large amount of carrier gas.
In order to obtain a large-area film with uniform characteristics and good quality, efforts are being made to improve the film growth rate, and to obtain a large-area film with uniform characteristics and good quality, it is necessary to ensure that the grown film thickness distribution is uniform and that the gas plasma generated by the discharge It is necessary to prevent spatial non-uniform distribution from occurring. Conventional methods are not fully satisfactory in these respects,
It was not possible to realize a device with the necessary performance in terms of production technology.

The present invention has been made in view of the above points, and is capable of producing a film with substantially uniform physical properties and film thickness over the entire area even if the film has a large area with good reproducibility. The main objective is to provide a method for forming a film that can be formed with high efficiency.

Another object of the present invention is to provide a method of forming a film that is extremely effective for mass products.

In addition, the present invention provides an extremely economical and highly productive film in which the discharge intensity can be made uniform over the entire film formation area, gas consumption can be reduced as much as possible, and the film growth rate is high. It is also an objective to provide a method of formation.

The film forming method of the present invention involves introducing a film forming gas into a deposition chamber that can be made under reduced pressure, and forming a film on a predetermined support using electrical discharge. When raised, they are arranged in a line substantially parallel to each other and substantially perpendicular to the support.
(2k−1)th and 2kth (k
= 1, 2, 3,...n), forming a potential difference between a pair of electrodes, and forming a flow of gas for film formation in the region between the electrodes where the potential difference is formed. It is.

According to the film forming method of the present invention, the film thickness and physical properties such as electrical, optical, or photoelectric properties can be made uniform over the entire area, and the film quality can be made uniform over a large area. It is extremely effective for forming photoelectric conversion layers for solar cells, electrophotographic photoreceptors, large-sized televisions, large-sized displays, etc., which require a large area.

Moreover, it is extremely economical and highly productive because it consumes less gas and has a higher film growth rate.
This can be applied on a corporate basis.

The film forming method of the present invention will be explained below with reference to the drawings.

FIG. 1 is an explanatory diagram schematically showing an outline of a preferred example of an apparatus that can embody the film forming method of the present invention, and FIG. 2 shows a part of the apparatus shown in FIG. 1 in detail. FIG. 2 is a schematic partial perspective view for explanation.

Inside the deposition chamber 101 of the apparatus 100 shown in FIG. , its tip is attached to the take-up roller 105 and preparations for film formation are made as shown in the figure.

A heater 106 is installed below the guide support plate 104 to heat the support 103 for film formation to a predetermined temperature during film formation, so that the support 103 can be heated as necessary. It's summery. There are many sheets (16 sheets in the figure) on the upper side of the support body 103.
The plate-shaped electrodes 107 are arranged in a horizontal line at predetermined intervals so as to be substantially parallel to each other and substantially perpendicular to the support 103.

In the figure, 16 plate-shaped electrodes 107 are arranged in pairs with adjacent ones to form six sets of discharge electrodes, and each set of discharge electrodes is electrically insulated and connected at the upper part. It is supported by a gas introduction pipe 108, and gas is introduced into the deposition chamber 101 through this gas introduction pipe 108 between the plate electrodes 107 constituting each set.

The 16 plate-like electrodes 107 are electrically connected every other pair in common, and by activating the power source 109, a potential difference is created between each set of electrodes.

When a film-forming gas is introduced from the gas introduction pipe 108 between each set of electrodes having a potential difference to form a gas flow, a discharge is caused in the region where the gas flows, and plasma of the gas is generated. It is formed.

During film formation, the surface of the support 103 is moved according to the winding operation of the winding roller 105, and a film-forming substance is deposited on the surface thereof. Therefore, by using the electrode arrangement and gas introduction method as shown in the figure, it is possible to equalize the film forming conditions in the direction perpendicular to the moving direction of the support 103, and the film forming substance is As a result, the film forming conditions in the moving direction can be equalized by the deposition of A film with uniform layer thickness and uniform properties can be formed on the support 103.

The moving speed of the support 103 during film formation depends on the characteristics required for the film to be formed, the gas flow rate, the type of gas, the magnitude of the potential difference formed between the electrodes 107, the type of support 103, and the deposition speed ( deposition rate), etc., and can be determined as desired according to these conditions. Gas introduced into the deposition chamber 101 is supplied through a gas introduction pipe 10.
cylinders 110-1, 110- connected to
2,110-3 to each valve 111-
It is supplied by opening 1,111-2,111-3.

For example, if an a-Si:H film is to be formed, the cylinder 110-1 contains silane such as SiH ₄ and the cylinder 110-2 contains gas for introducing impurities, pH ₃ ,
B ₂ H ₆ , etc., and the cylinder 110-3 is filled with Ar, He, etc. as a diluting gas, and these gases are adjusted by adjusting the degree of opening of the valves 111-1, 111-2, and 111-3. in the deposition chamber 10 at the desired mixing ratio.
1.

To reduce the pressure inside the deposition chamber 101,
This is accomplished by opening the main valve 113 through an exhaust port 112 provided at the lower portion of the exhaust system 114 to exhaust the inside.

As the exhaust device 114, a commonly used device is adopted; for example, if the deposition chamber 101 is to be brought to a low vacuum level, a rotary pump or the like may be sufficient.
If it is necessary to create an even higher vacuum, use a diffusion pump or the like.

In the device having the electrode arrangement structure shown in FIG. 1, a flow of gas is formed to flow out from each outlet of the gas introduction pipe 108, as indicated by the arrows in the figure.

Formation of such a gas flow has a synergistic effect with the electrode arrangement structure, and is highly effective in making the density of the formed plasma uniform.

In addition, the plasma atmosphere that is formed is spatially subdivided by using the electrode arrangement structure shown in the figure and the formation of the electric field by employing a large number of plate-shaped electrodes, so that the shape, size, and material of the electrodes can be controlled. The non-uniformity of the electric field due to variations can be averaged out to make it substantially uniform, and the reproducibility and characteristics of the film can be dramatically improved.

Further, the electrode array structure as shown in the figure can form a plasma atmosphere with almost no spatial variation, almost regardless of the size of the device.
Therefore, even if the size of the device is increased according to the production plan in order to increase the production volume, there is almost no need to make any design changes due to the increase in size.

Furthermore, if the electrode arrangement structure and gas introduction method shown in FIG. 1 are adopted, the introduced gas is effectively consumed for film formation, so the amount of unused gas discharged outside the deposition chamber 101 is extremely reduced. gas consumption can therefore be significantly reduced.

FIG. 2 is a partial perspective view showing in detail the electrode array structure and shape of the device shown in FIG. 1.

a set of electrodes, e.g. electrode 107-1 and electrode 10
7-2, the upper part is roof-shaped and electrically insulated from each other, and the gas introduction pipe 108
It has an integral structure with the analysis pipe 108-1.

The tip of the analysis pipe 108-1 is T-shaped and has many pores opened on the side facing the support 103 to allow gas flow between it and the electrodes 107-1 and 107-2. can be formed.

The distance provided between the electrode 107 and the support 103 is usually 0.5 to 6 mm, preferably 1 to 6 mm.
It is said to be 5mm.

Further, the arrangement interval of the plate electrodes can be appropriately determined based on the correlation with other film forming conditions, but it is usually desirable to set it to 2 to 5 cm.

The potential difference formed between the pair of plate-like electrodes may be caused by direct current or alternating current, but in the case of the present invention, alternating current in the RF (radio frequency) region is preferably employed.

An example of a case where a film is actually formed using the apparatus shown in FIG. 1 is that, for example, the distance between the plate electrodes is maintained at 3 cm, the internal pressure of the deposition chamber 101 is 0.1 Torr, and the reaction gas flow rate is 0.1 cc/sec. , SiH ₄ /Ar= as reaction gas
1/10, the distance between the tip of the plate electrode and the support is 2 mm
When electrical energy of 13.56MHz and 50W is applied to the plate electrode, the film growth rate is 10 Å/sec, which shows extremely good electrical and optical properties.
A Si:H film could be formed over a large area with good reproducibility.

[Brief explanation of the drawing]

FIG. 1 is a schematic explanatory diagram showing one of the apparatuses for embodying the film forming method of the present invention, and FIG.
1 is a partial perspective view showing some details of the illustrated device; FIG. 100... Deposition device, 101... Deposition chamber, 10
2... Supply roller, 103... Support body, 104...
...Guide support plate, 105... Winding roller, 106...
... Heater, 107 ... Plate electrode, 108 ... Gas introduction pipe, 109 ... Power supply, 110 ... Cylinder, 111 ... Valve, 112 ... Discharge port, 11
3...Main valve, 114...Exhaust device.

Claims (1)

[Scope of Claims] 1. In a film forming method in which a film forming gas is introduced into a deposition chamber that can be reduced in pressure and a film is formed on a predetermined support using electric discharge, an electric discharge is introduced into the deposition chamber. When raising, the (2k-1)th and
2k numbers (k = 1, 2, 3...n) to form a potential difference between a pair of electrodes, and to form a flow of gas for film formation in the region between the electrodes where the potential difference is formed. Characteristic film formation method.