JPH0722326A - Optical cvd device - Google Patents

Abstract

PURPOSE:To provide the title optical CVD device capable of avoiding the choking of rectifying gas at blowing-out ports even during long term film forming step for making the step feasible. CONSTITUTION:In order to deposit a thin film on a substrate 5 arranged in a reaction chamber 1 by irradiating the gas fed in the reaction chamber 1 through a rectifying gas blowing-out port 6 with light beams from light sources 3 such as low pressure mercury lamps etc., through an incident light window 2 to accelerate the photochemical reaction, baffer plates 4 are arranged so that the rectifying gas blowing-out port 6 may not be irradiated with the beams fed from the light sources 3 to the reaction chamber 1 through the incident light window 2. Furthermore, the baffer plates 4 are longer toward the rectifying gas blowing port 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photo-CVD apparatus, and more particularly to a photo-CVD apparatus suitable for preventing clogging of an outlet of a gas supply pipe in an apparatus for forming a thin film using a photochemical reaction. .

[0002]

2. Description of the Related Art A photochemical reaction promotes a chemical reaction by irradiating a reactive gas with light having a wavelength corresponding to the wavelength absorption of the gas. The reaction can be selectively proceeded by the combination of the irradiation light and the reaction gas. Furthermore, the photochemical reaction does not require a high temperature like a thermochemical reaction, so it is effective in lowering the temperature of the process and does not have the effect of charged particles like a plasma reaction.
Since the deposited film has no electrical damage, it is said to be effective for forming a silicon oxide film or the like.

However, in a thin film manufacturing apparatus using a photochemical reaction, a reaction gas is supplied into a reaction vessel to deposit a thin film on a substrate, so that the number of times of depositing the thin film increases or the thin film is deposited. If the time is increased, the reaction product adheres to the surface of the light incident window, the intensity of the light irradiated into the reaction vessel decreases, and the reaction is stopped.

The present inventors have previously proposed the photochemical reaction device shown in FIG. 3 as a thin film manufacturing device for preventing the reaction products from adhering to the surface of the light incident window. (JP-A 1-1
(86613 publication)

In FIG. 3, 51 is a reaction chamber, 52 is a light incident window forming a part of the wall surface of the reaction chamber 51, 53 is a light source, 54 is a substrate for depositing a thin film, and 56 is a photochemical reaction. A non-related gas, 57 is a reaction gas, 58 is a rectifying gas outlet, and 59 is an exhaust port.

In the photochemical reaction device described above, the light entrance window 5
In order to prevent the reaction product from adhering to the surface of No. 2, the gas outlet 58 is made of a heat-resistant porous material having a large number of fine communication holes, and the gas flow channel shape is disturbed by the gas flow. The structure does not have unevenness that causes

However, although the light from the light source 53 passes through the light incident window 52 and irradiates the vicinity of the substrate 54, it also irradiates the rectified gas outlet 58. Therefore, when the photochemical reaction proceeds in the vicinity of the rectified gas outlet 58, a film is deposited also on the rectified gas outlet 58, and the rectified gas outlet 58 is likely to be clogged.

[0008]

As described above, in the conventional photochemical reaction device, the light from the light source 53 is transmitted to the substrate 5.
Although it is configured to irradiate in the vicinity of No. 4, there is no particular consideration so as not to irradiate the rectifying gas outlet 58. For this reason, when the photochemical reaction proceeds in the vicinity of the rectified gas outlet 58, a film is formed in the communication hole, and the rectified gas outlet 58 is likely to be clogged.

An object of the present invention is to solve the above-mentioned problems of the prior art and to provide an optical CVD apparatus capable of preventing clogging of a rectifying gas outlet even if a film forming operation is performed for a long period of time.

[0010]

In order to achieve the above-mentioned object, the present invention irradiates the gas supplied into the reaction chamber through the rectifying gas outlet with the light from the light source through the light entrance window. In a photo-CVD apparatus that promotes a photochemical reaction by means of and deposits a thin film on a substrate installed in the reaction chamber, the light supplied from the light source into the reaction chamber through the light incident window is prevented from being irradiated to the rectified gas outlet. The feature is that a shielding plate is installed near the light source.

[0011]

When the reaction gas supplied into the reaction chamber is not irradiated with light having a wavelength necessary for exciting the reaction gas, the photochemical reaction is not promoted and the reaction product is not generated. Since the irradiation of the light from the light source is shielded by the shielding plate near the rectifying gas outlet, the photochemical reaction is not promoted near the rectifying gas outlet and the reaction product is not generated. As a result, no film is generated at the rectified gas outlet,
Clogging of the rectified gas outlet is prevented.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic sectional configuration diagram showing an embodiment of the photo-CVD apparatus of the present invention. A light incident window 2 is installed above a reaction chamber 1 that constitutes the inside of a reaction vessel having an internal space with a rectangular cross section. The light entrance window 2 constitutes a part of the wall surface of the reaction chamber 1, and the inner wall surface of the reaction chamber 1 and the inner surface of the light entrance window 2 (reaction chamber side surface) are flush with each other and have a structure having no unevenness. ing.

A plurality of low-pressure mercury lamps 3 serving as excitation sources for photochemical reactions are arranged above the light entrance window 2, and a shielding plate 4 is provided between the low-pressure mercury lamps 3. The windows 2 are arranged side by side in a direction perpendicular to the windows 2.

Further, a recess is formed in the bottom surface of the reaction chamber 1, and a susceptor 9 having a shape in which a substrate 5 for depositing a thin film can be embedded is provided in the recess, and the susceptor 9 and the substrate 5 are formed. The upper surface is flush with the bottom surface of the reaction chamber 1 and has a structure having no unevenness.

A rectifying gas outlet 6 is provided on the side surface of the reaction vessel, and the rectifying gas outlet 6 is divided into two stages in the vertical direction, and the lower side thereof alone is a cause of clouding of the light incident window 2. A gas supply pipe 7 for supplying a reaction gas that may possibly become a gas supply pipe is provided, and a gas supply pipe 8 for supplying a reaction gas that does not cause fog of the light incident window 2 by itself is provided on the upper side thereof. It is arranged. An exhaust port 10 is formed below the side surface of the reaction chamber 1 corresponding to the rectified gas outlet 6.

The rectifying gas outlet 6 is made of a heat-resistant porous material having a large number of fine communication holes, and the porous material has, for example, an average particle diameter of 0.1 μm to 1 mm, preferably. Is preferably made of a sintered body of metal or ceramic having a thickness of 2 μm to 500 μm.

When the low-pressure mercury lamp 3 irradiates light into the reaction chamber 1 through the light entrance window 2, the shielding plates are provided so that the rectifying gas outlet 6 is not irradiated with light as shown by the dotted line in FIG. The length of 4 is different. That is, the low-pressure mercury lamps 3 are arranged in parallel in parallel with the light incident window 2 at a predetermined interval, and the respective shielding plates 4 arranged in the direction perpendicular to the light incident window 2 are rectified. The length of the shielding plate 4 on the gas outlet 6 side is long, and the length of the shielding plate 4 decreases on the side of the exhaust port 10.

The operation of the photo-CVD apparatus having the above-mentioned structure will be described below by taking as an example the case of depositing a silicon oxide film (Si2 O) using monosilane (SiH4) and oxygen gas (O2).

In the apparatus shown in FIG. 1, monosilane gas is supplied from the gas supply pipe 7 into the reaction chamber 1 through the lower rectifying gas outlet 6, and oxygen gas is supplied from the gas supply pipe 8 to the upper rectifying gas outlet 6. Through the inside of the reaction chamber 1. Usually, the film formation is carried out under reduced pressure, but under the reduced pressure, immediately after the monosilane gas and the oxygen gas are supplied into the reaction chamber 1 at the same flow rate, they spread by mutual diffusion and mix with each other.

At this point, the photochemical reaction proceeds if the light from the low-pressure mercury lamp 3 is radiated, but in the vicinity of the rectifying gas outlet 6, there is formed a region where the light is not radiated. Does not progress. Therefore, since the reaction product is not generated in the region near the rectified gas outlet 6, the reaction product does not adhere to the rectified gas outlet 6. When the reaction gas enters the area shown by the dotted line in FIG. 2, the photochemical reaction proceeds, and as a result, a thin film is deposited on the substrate 5, but the reaction product does not adhere to the rectifying gas outlet 6.

[0021]

As described above, according to the present invention, even if the film forming operation is continued for a long time or for a long period of time, the rectifying gas outlet is not clogged and the film forming operation can be stably performed.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional configuration diagram showing an embodiment of a photo-CVD apparatus of the present invention.

FIG. 2 is an explanatory diagram showing a light irradiation area in the apparatus of FIG.

FIG. 3 is a schematic cross-sectional configuration diagram showing a conventional photochemical reaction device.

[Explanation of symbols]

 1 Reaction chamber 2 Light entrance window 3 Low-pressure mercury lamp 4 Shielding plate 5 Substrate 6 Rectifying gas outlet 7, 8 Gas supply pipe 9 Susceptor 10 Exhaust outlet

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Saburo Ataka 1-2-10 Isogo, Isogo-ku, Yokohama-shi, Kanagawa Babcock Hitachi Ltd. Yokohama Research Laboratory

Claims (2)

[Claims] 1. A photochemical reaction is promoted by irradiating a gas supplied into a reaction chamber through a rectifying gas outlet through a light incident window with light from a light source, thereby promoting a photochemical reaction, and on a substrate installed in the reaction chamber. In the photo-CVD apparatus for depositing a thin film on the substrate, a shielding plate is installed near the light source so that the light supplied from the light source into the reaction chamber through the light incident window is not irradiated to the rectifying gas outlet. Photo CVD equipment. 2. A plurality of the light sources are arranged in parallel in parallel with a light entrance window forming a part of the reaction chamber, the shielding plate is installed between the light sources, and the rectifying gas blowout port side is provided. 2. The photo-CVD apparatus according to claim 1, wherein the shield plate has a length that becomes longer as the shield plate comes closer to the shield plate.