JPH0372712B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a photochemical reaction device.

Recently, research has been conducted into methods for forming thin films of amorphous silicon used in photosensitive drums of electronic copying machines, solar cells, and the like. On the other hand, vapor deposition methods are also used to form various insulating films and protective films, and various vapor deposition methods have been proposed depending on the application. The formation rate is extremely fast, and it has recently attracted particular attention.

In the chemical vapor deposition or deposition method that utilizes this photochemical reaction, a substrate is placed inside a reaction vessel that has a window that allows ultraviolet rays to pass through, a photoreaction gas is passed through the substrate, and an ultraviolet light source is used from outside the vessel to convert the gas into a photochemical reaction. The reaction product is vapor-deposited or deposited on a substrate, and has the above-mentioned major advantages. Also, compared to other conventional vapor deposition methods,
This photochemical vapor deposition or deposition method can form a relatively uniform film even on a large area, but recently, due to the demand for quality improvement, the importance of film uniformity has become more and more important, and the variation in film thickness has been reduced to 2 to 2. It is required to be within about 3%. By the way, in the conventional photochemical vapor deposition or deposition method, an introduction hole for the photoreactive gas is provided in the side wall of the container, and the photoreactive gas flowing on the substrate is irradiated with ultraviolet rays. It was difficult to flow the photoreactive gas uniformly over the area, and it was not possible to completely satisfy the above-mentioned degree of uniformity.

Therefore, an object of the present invention is to provide a photochemical reaction device that has a simple structure and can uniformly flow a photoreactive gas over a wide area of a substrate and form a uniform film. , a reaction vessel having an ultraviolet ray transmission window, a gas supply/exhaust mechanism for supplying a photoreactive gas into the reaction vessel, and an ultraviolet light source that irradiates a substrate, which is an object to be processed, from outside the reaction vessel through the transmission window. The air supply member of this gas supply and exhaust mechanism includes pipe members that transmit ultraviolet rays arranged in a planar shape in a grid or comb pattern, and a large number of gas outlet holes in the pipe members. The air supply member covers the transmission window, and the gas outlet hole is arranged so as to face the air plate.

The present invention will be specifically described below based on embodiments shown in the drawings.

A substrate support stand 13 made of quartz glass is arranged in the center of the interior of the reaction vessel 1 so as to be movable up and down. The top surface is a UV transmitting window 1 made of quartz glass.
4, a lamp body 2 is integrally provided above the lamp body 2, and a plurality of ultraviolet lamps 3, which are ultraviolet light sources, are arranged in parallel on the ceiling of the lamp body 2 via a reflective member 21. Here, the tube diameter of UV lamp 3 is 18
mm, the lighting starting voltage is 350V, the lighting voltage is 90V, and the current is 5A.It is an AC lighting low-pressure mercury lamp, but it is not limited to this, and electrodeless lamp devices or plasma generators may also be used. Any device that generates a fixed amount of ultraviolet light may be used. Further, if necessary, the interior of the lamp body 2 can be made to flow with gas or to be evacuated by a gas supply/discharge mechanism.

A temperature controller (not shown) is attached to the substrate support stand 13, and the substrate 4 supported by this has an outer diameter of
It is a 160mm alumina plate heated to approximately 150℃. Note that this substrate support stand 13 can be made rotatable like a turntable or movable within the reaction vessel 1, so that a large number of substrates 4 can be efficiently processed by loading and unloading the substrates 4 with a transport mechanism. .

Next, the air supply member 5 of the photoreactive gas supply and discharge mechanism has a planar shape and is disposed on the substrate support 13 in parallel thereto. In this embodiment, this is made up of quartz glass pipe members arranged in a comb pattern, and is arranged so as to cover the transmission window 14. As shown in FIG. 2, a large number of gas outflow holes 51 are provided on one side of the gas outlet 51, which faces the substrate 4 placed on the substrate support 13. From the introduction pipe 52,
Argon as carrier gas, mercury gas as photosensitizer,
A mixed gas consisting of silicon tetrahydride as a decomposition vapor deposition gas is supplied and flows out from the outflow hole 51.
Note that this air supply member 5 is made of pipe members that transmit ultraviolet rays woven into a grid or mesh shape. In this way, since the air supply member 5 is a pipe member that transmits ultraviolet rays and is arranged in a plane like a lattice or comb shape, the spacing of the pipe members can be changed as necessary to achieve density. be able to. That is, since the photoreactive gas guided by the introduction pipe 52 tends to flow into the pipe members near the introduction pipe 52 in large quantities, the intervals between the pipe members near the introduction pipe 52 are made coarse, and both ends are closely spaced. For example, the outflow of the photoreactive gas from the air supply member 5 can be made more uniform. In the photochemical reaction device, the air supply member 5 that covers the ultraviolet-transmitting window is made of a material that transmits ultraviolet rays, such as quartz glass, and the ultraviolet transmittance of quartz glass, for example, is about 90%.
Therefore, by varying the spacing between the pipe members, the light intensity distribution can be adjusted, and the light intensity distribution with respect to the substrate 4 can be made uniform. After all, by configuring the air supply member 5 with a pipe member, both the flow of the photoreactive gas and the light intensity distribution with respect to the substrate 4 can be made uniform. The air supply member 5 is preferably provided with a temperature regulator to adjust each gas to an optimum temperature to promote photochemical reactions. An exhaust hole 6 connected to a decompression device is provided on the lower surface of the reaction vessel 1, which is the back of the substrate support 13, so that the photoreactive gas flows uniformly from the top to the bottom, symmetrically to the center line. It's getting old.

In the above apparatus, the pressure inside the reaction vessel 1 is reduced and the ultraviolet lamp 3 is turned on. However, the photochemical reaction may be caused under normal pressure without reducing the pressure inside the reaction vessel 1. Then, from the air supply member 5,
5 mmHg argon, 3 mmHg silicon tetrahydride, 3
×10 ^-3 mmHg mercury vapor is introduced, and ultraviolet light passes through the transmission window 14 and the air supply member 5 and irradiates the substrate 4. As a result, silicon tetrahydride is photodecomposed, and amorphous silicon is transferred to the substrate. 4. At this time, since the air supply member 5 is planar and has a large number of outflow holes 51 provided on one side facing the substrate 4, the photoreactive gas flowing out from these outflow holes 51 forms a parallel layer. The liquid flows onto the substrate 4 in a flowing state. Therefore, even if the area of the substrate 4 is large, it flows uniformly over the entire surface and is irradiated with ultraviolet rays in this state, so that the thickness of the vapor-deposited or deposited film is also uniform, and variations can be made very small. Incidentally, it has been found that the variation in film thickness when deposited under the above conditions can be kept within 1%, and the above target value can be fully achieved.

As explained above, in the photochemical reaction device of the present invention, the air supply member of the gas supply/discharge mechanism has pipe members that transmit ultraviolet rays arranged in a plane like a lattice shape or a comb shape, and a large number of pipe members in the pipe members This air supply member covers the transmission window, and the gas outlet hole is arranged to face the substrate, so that the photoreactive gas can be uniformly distributed over a large area of the substrate. According to the present invention, it is possible to provide a photochemical reaction device capable of forming a uniform film.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention, and FIG. 2 is a perspective view of an air supply member. DESCRIPTION OF SYMBOLS 1... Reaction container, 2... Lamp, 3... Ultraviolet lamp, 4... Substrate, 14... Transmission window, 5... Air supply member, 51... Gas outflow hole, 6... Exhaust hole.

Claims (1)

[Claims] 1. A reaction vessel having an ultraviolet ray transmission window, a gas supply/exhaust mechanism for supplying a photoreactive gas into the reaction vessel, and an ultraviolet light source that irradiates the substrate, which is the object to be processed, from outside the reaction vessel through the transmission window. In the photochemical reaction device, the air supply member of the gas supply/discharge mechanism includes pipe members that transmit ultraviolet rays arranged in a plane in a grid or comb pattern, and a large number of gas outlet holes in the pipe members. A photochemical reaction device, characterized in that the air supply member covers the transmission window and is arranged so that the gas outlet hole faces the substrate.