JPS5938373A - Plasma cvd device - Google Patents

Abstract

PURPOSE:To deposit uniformly a photosensitive film, etc. on a substrate, by providing holes for releasing a gaseous raw material on a discoid electrode disposed in vacuum chamber radially from the center of the side face of the electrode and providing a pipe for supplying the gas to the array of said holes. CONSTITUTION:A discoid base body 2 is set in a vacuum chamber 3, and a discoid electrode 1 is disposed oppositely to the body 2. Holes 11 for releasing gas are opened in a radial array to the electrode 1 from the center of the side face and one metallic pipe 12 of a semicircular sectional shape for supplying gas for the same array of the holes 11 is mounted. The body 2 is rotated under heating with a heater 5 to make the temp. distribution of the body 2 uniform. The gaseous raw material fed through a gas supply pipe 8 is fed to the radially expanded pipe 12, and is released from the holes 11 toward the body 2. A high frequency voltage is applied to the electrode 1 to generate glow discharge between the electrode and the body 2 and to cause radical reaction of the gaseous molecules, thereby forming an amorphous silicon film, etc. on the body 2.

Description

[Detailed description of the invention]

The present invention is a plasma CV method for forming a deposited film on a substrate.
D equipment relates to the production of photodetectors using amorphous silicon photoreceptors, in particular, the production of photodetectors using plasma CVD technology to deposit an amorphous silicon film on the surface of a flat substrate. Silicon nitride (SIN)
membrane, silicon oxynitride (SiON) membrane, silicon oxide (SI02) membrane, silicon carbide (
The present invention relates to a plasma CVD apparatus capable of continuously depositing a StC film on the surface of the photoreceptor to improve the moisture resistance and abrasion resistance of the light receiving element. In the following description, the present invention will mainly be explained with reference to embodiments in which the substrate is a flat substrate for a light-receiving element. By depositing a hard film such as silicon carbide (SiC) film on the surface of tools that are prone to deterioration, it can be used to improve the wear resistance of tools and extend their useful life. It can also be used for the purpose of depositing a film such as a silicon oxide (Sin2) film as an undercoat material on the surface of an acrylic aspheric lens, etc., to enable the deposition of an optical thin film on the surface of an acrylic aspheric lens. . FIG. 1 shows a typical example of a conventional parallel plate wall emission type plasma CVD apparatus used as an apparatus for forming a deposited film on a substrate as described above. In the figure, 1 is a cathode electrode, 2 is a circular plate-like base that constitutes an anode electrode, 3 is a vacuum chamber, 14 is an insulating insulator, 5 is a heater for heating the base, 6 is a motor for rotating the base, and 7 is a base for rotating the base. Exhaust system, 8 is a raw material gas supply pipe, 9 is a high frequency power source that generates glow discharge in vacuum, 10 is a ground 1.1 that uses a circular flat substrate as an anode electrode.
1 is a discharge hole for raw material gas. As shown in the figure, the cathode electrode has a circular flat plate double structure, and a chamber to which source gas is supplied is formed inside the cathode electrode. The operation of the above device is as follows. First, the disc-shaped base 2 is set in the chamber 3, and the inside of the chamber is evacuated by the exhaust system 7. At the same time, the base 2 is heated by the heater 5, and the base 2 is heated by the motor 6.
rotates to make the temperature distribution of the substrate uniform. At this time, the heater is fixed. When the substrate temperature becomes constant, raw material gas is supplied into the vacuum chamber 3 from the gas supply IP igu 8. The gas is released from the release hole] 1 toward the substrate, and with the raw material gas being supplied into the , earthing] A glow discharge is generated between the substrates 2 which are set to 0, and electrons ejected from the cathode 6 poles collide with gas molecules, causing a radical reaction of the gas molecules and depositing them on the substrate, forming an amorphous silicon film. In the above-mentioned plasma CVD apparatus, the thickness distribution of the deposited film depends on the position of the exhaust port of the apparatus, the flow rate of the raw material gas, the film deposition rate depending on the magnitude of the high-frequency power during discharge, and even It varies depending on the degree of vacuum and the position of the raw material gas discharge hole. Considering the purpose of using the amorphous/licon photoreceptor film, it is required to uniformly distribute the film thickness over a wide range on a large substrate. Plasma CVD In the device, the gas flow rate, the magnitude of high-frequency power, the degree of vacuum, etc. affect the film properties and cannot be used as a means to adjust the film thickness distribution.The position of the exhaust port also depends on the device configuration. It is difficult to freely change the film thickness distribution.In other words, the easiest way to adjust the film thickness distribution is to adjust the hole diameter and position of the gas discharge holes.On the other hand, in plasma CVD equipment, specific It is necessary to select the gas flow rate and flow rate in order to obtain the film characteristics, and since the dust film thickness distribution changes each time, it is required that the hole diameter and position of the gas discharge port have a high degree of freedom in selection. Most conventional parallel plate wall-emission plasma CVD devices have a large number of raw material gas discharge holes opened irregularly or a large number of holes arranged around the circumference. It was difficult to select the optimal hole position to make the distribution uniform.Also, since little consideration was given to the degree of freedom of the hole diameter, adjustment of the film thickness distribution depended only on the selection of the hole position. For this reason, the conventional apparatus had the disadvantage that as the effective deposition range became wider, it became more difficult to adjust the film thickness distribution. In order to significantly improve the adjustment, the cathode electrode is made into a disk shape arranged parallel to the substrate, and gas release holes opened in the wall surface of the cathode electrode are placed in parallel to the substrate.

[ is opened with a radiating warp from the center of the polar one law surface, and the number of holes of this gas release hole is set to 1 to 10 holes in proportion to the surface area of the base, and for one row of holes " IL and others + lil + One gas supply 9 Ig is installed on the wall surface, and the membrane J: J-min (by limiting the numerical aperture to the extent that there is no problem with H,
This clarifies the correlation between the film thickness distribution and the opening position of the gas release hole, making it possible to easily adjust the film thickness distribution. However, by rotating the above-mentioned substrate around the central axis, uniformity of the film thickness is ensured. Furthermore, by providing discharge ports with different hole diameters on the screws attached to the gas discharge holes, it is possible to finely adjust the film thickness distribution, making it possible, for example, to uniformly deposit an amorphous silicon photoreceptor film on a large-area substrate. It is. The present invention will be described in detail below based on an example device. FIG. 2 shows an embodiment of a plasma CVD apparatus according to the present invention. In the figures, parts similar to parts in the apparatus shown in FIG. 1 are designated by the same reference numerals. In the figure, 1 is a cathode electrode, and 2 is a disk-shaped base forming an anode electrode, which is rotated by a rotation motor during the deposition process. 3 is a vacuum chamber; 4 is an insulating insulator for electrically insulating the cathode electrode, the vacuum chamber, and the anode electrode; 5 is a heater for heating the base attached to the anode electrode; 6 is a rotating disc-shaped base 7 is an exhaust system for keeping the chamber in a vacuum, 8 is a raw material gas supply pipe, 9 is a high frequency power source for generating glow discharge between the cathode electrode and anode electrode, 10 is the anode electrode and the vacuum chamber is a ground for grounding, and numeral 11 indicates a hole for discharging the raw material gas for supplying the raw material gas into the glow chamber. A disk-shaped base 2 forming an anode spear is arranged in a vacuum chamber 3, and a cathode electrode 1 is formed in a disk-shape and arranged parallel to the substrate. The gas holes 1 for discharging the raw material are opened in radial rows (6 rows in the illustrated example) from the center of the side surface of the electrode, and one gas hole with a semicircular cross section is opened for each row. A supply metal pipe f12 is attached to the side surface of the electrode by welding. The holes 11 through which the source gas is released are threaded so that unnecessary holes can be closed with screws when adjusting the thickness distribution of the film deposited on the surface of the substrate. In addition, a screw with a gas release port in the center is installed in the threaded hole 11 described above, and a screw with a hole diameter of the gas release port is installed to change the amount of gas released and thereby distribute the film thickness. can be adjusted. In this way, the amount of gas released from each row of gas release holes can be adjusted independently. FIG. 3 shows the cathode electrode of the above device viewed from the anode electrode side, where ] is the cathode electrode and 1
Reference numeral 1 denotes gas discharge holes opened in six rows radially from the center. FIG. 4 shows a view of the cathode electrode of the above device viewed from the A empty chamber side, where ] is the cathode electrode;
Reference numeral 12 denotes six metal pipes welded radially from the center so as to correspond to the gas discharge ports in the same row, and supply raw material gas to the gas discharge ports in each row. Reference numeral 8 denotes a gas supply source for supplying raw material gas to each metal pipe. FIG. 5 shows a cross section of the cathode t4tA of the above device. In the figure, 1 is a cathode electrode, 11 is a cathode with gas release holes opening radially from the center of the electrode, and 12 is a semicircular cross section welded to the side wall of the vacuum chamber of the cathode electrode to supply gas to each gas release hole. It is a metal pipe. Figures 6(a) and 6(b) show a hexagon socket head to be attached to the gas discharge hole of the above device, and in Figure C(a),
Reference numeral 13 denotes a hexagon socket head screw provided with a gas discharge port, and 14 a gas discharge port. By replacing the screws with different hole diameters, the amount of gas released can be changed and the film thickness can be controlled. In FIG. 6(b), 5 is a hexagonal hole screw without a gas discharge port, and is used for the purpose of closing the gas discharge port that is no longer needed when adjusting the film thickness distribution. Next, the operation of each part of the above device will be explained in order. First, a disk-shaped base 2 is set in a chamber, and the inside of the chamber is made 32 by an exhaust system 7. At the same time, the entire base 2 is heated by the heater 5, and the base 2 is rotated by the motor 6 to make the temperature distribution of the base uniform. At this time, the heater is fixed. When the temperature of the substrate becomes constant, raw material gas is supplied from the gas supply tube 8 into the vacuum chamber. The raw material gas is sent to the metal pipe 12 that spreads out radially, but the flow rate is suppressed because the space in the pipe becomes narrow.
Gas is supplied evenly to each i4 Eve.・The gas flowing through the tube is released toward the base through the release hole 1]. The amount of gas released from each discharge hole is controlled by the diameter of the hole drilled in the screw attached to the discharge hole. With gas being stably supplied into the vacuum chamber 9, a high frequency voltage is applied to the cathode electrode 1 by a 13.56 MHz high frequency power source 9, and a glow discharge is generated between the grounded base 2. The electrons generated and ejected from the cathode electrode collide with the gas molecules, causing the gas molecules to undergo a radical reaction and deposited on the substrate, thereby forming the entire amorphous silicon film. As explained above, the plasma CVD apparatus according to the present invention reduces the number of raw material gas discharge holes opened in the cathode electrode and arranges them in a straight line in the direction normal to the rotation direction of the disk-shaped base. This has the effect of facilitating adjustment of film thickness distribution in the normal direction. Furthermore, by opening gas discharge ports with different hole diameters in the hexagonal socket screws attached to the gas discharge holes, the gas outlet can be adjusted by cutting in the normal direction, making it possible to fine-tune the film thickness distribution. This has the effect of In addition, the same row of raw material gas release holes opened at the cathode's end pole each has its own semicircular pipe for gas supply, so the gas pattern changes when the gas release holes in other rows are opened or closed. This has the effect of making it easier to adjust the amount of gas released from the same film, that is, adjust the film thickness distribution. Furthermore, even when depositing a film on a large-area substrate, for which adjustment of the film thickness distribution would be complicated using conventional equipment, the use of the present invention makes it easy to adjust the film thickness distribution. This has the effect of improving the reproducibility of the laminated film characteristics.
This has the effect of stably producing light receiving elements, which is one of the purposes for which TW is used.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway perspective view showing a conventional plasma CVD apparatus, Fig. 2 is a partially cutaway perspective view showing an embodiment of the plasma CVD apparatus of the present invention, and Fig. 3 is shown in Fig. 2. Figure 4 is a view of the cathode electrode viewed from the vacuum chamber 11111, Figure 5 is a cross-sectional view of the cathode electrode, and Figure 6 (I) (B) shows gas release. It is a 11111 side view of a hexagon socket head screw attached to a hole. 1... Cathode electrode 2... Disc-shaped base 3.
...Vacuum chamber 4...Electric insulation insulator 5...
Heater for heating the substrate 6...Motor for rotating the substrate 7.
・・Exhaust system 8・・Original M gas supply pino 9
...High frequency'@source 10...Earth 11...
・Gas release hole 12...Semi-circular metal/J'ino J3...Hexagonal hole with gas release port]4...
Gas release port] 5... Hexagonal socket with a hole to block the gas release port (Figure 1)

Claims (1)

[Claims] (1) A disc-shaped base is placed in a vacuum chamber 9-, and a reservoir hole for releasing source gas is provided on the side of a disc-shaped electrode placed parallel to the base. A plasma CVD characterized in that a large number of openings are formed in a radial row from the center of the side surface of the electrode, and one arm (for gas supply) is provided on the side wall surface of the electrode for each row of holes. Device. (2) When adjusting the film thickness distribution of the film deposited on the surface of the disk-shaped substrate by drilling a screw hole into the hole through which the raw material gas is released, the unnecessary hole can be plugged with a screw. The plasma CV according to claim (1), which is
D device. (3) Machine a screw hole in the hole that releases the raw material gas,
By attaching a screw with a gas release port in the center to this screw hole, and installing a screw with a different hole diameter for the release port into the screw hole, you can change the amount of gas release and adjust the film thickness distribution. Plasma CV according to claim (1)
D device.