JPH0266174A - Optical CVD equipment - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Industrial application field The present invention converts raw material gas into active species by photochemical reaction,
It is connected to a thin film forming apparatus (photo-CVD apparatus) that deposits a thin film on a substrate E installed in a reaction chamber.

Conventional technology Optical CVD (Chemical Vapor De
position: chemical vapor deposition) method is plasma CV
Compared to method D, there is no damage to the deposited film because it does not use charged particles.
+-xCx: This is an effective thin film forming method for forming films such as HlS i Ox.

Conventional general optical CVD equipment currently in use uses a lamp (mercury lamp, xenon lamp, etc.) or a laser (Ar laser, co-laser, ArF laser, etc.) as a light source to perform a photochemical reaction on the raw material gas (SiH4:
Silane, 5i2Hs Nidisilane, etc.) are used as active species to deposit a film on a substrate. At this time, the light source room (
The chamber containing the lamp or laser is kept airtight from the source gas, and the light from the light source chamber is passed through the light source window made of a translucent material (quartz, synthetic quartz, etc.) to deposit the film on the reaction chamber (substrate L). The structure is such that the raw material gas introduced into the reaction chamber is converted into active species.

Problems to be Solved by the Invention However, for example, when attempting to deposit an a-3r:H film using a conventional photo-CVD apparatus, the 5i2Ha used as the source gas is 254 nm (4,88 eV), 18
It is decomposed by light with a wavelength of 5 nm (6.7 eV), producing active species and depositing an a-9i:H film on the substrate. However, this a-9i:H film is deposited not only on the substrate but also on the light source window. Here, the optical gap of the a-5i:H film is about 1.8 eV (about 700 n), and the a-5i:H film deposited on the light source window is
It absorbs light that causes a photochemical reaction with a wavelength of 185 nm and t' L/. Therefore, the photochemical reaction is inhibited, and the a-9i:H film can only be deposited to a thickness of several tens of OA at a time using a conventional photo-CVD apparatus.

In order to solve this problem, a method has been adopted to prevent film deposition on the light source window by flowing a diluent gas onto the surface of the light source window in addition to the raw material gas in the reaction chamber (for example, JP-A No. 6
0-74427).

However, since this method attempts to create a laminar flow state in the reaction chamber in a vacuum state, a stable N flow does not occur between the raw material gas and the diluent gas, and the gases mix, resulting in a film forming on the light source window. It will accumulate.

In addition to this, in order to prevent film from accumulating on the light source window,
Another method is to apply oil to the light source window, but it is not used often because the oil gets mixed into the film.

Means for Solving the Problems As described above, in the conventional optical CVD apparatus, a film is deposited on the light source window, making it difficult to deposit an a-9i:H film or the like. Therefore, the optical CVD apparatus of the present invention does not provide a light source window directly between the reaction chamber and the light source chamber, but instead includes a light source and an airtight tube (hereinafter referred to as ,
・One or more reaction tubes (referred to as reaction tubes) are installed. Furthermore, the portion before the gas is introduced into the reaction tube is made into a double-structured tube, so that the source gas flows through the center and the diluent gas flows toward the inner wall of the reaction tube.

In the present invention, the raw material gas is not directly introduced into the reaction chamber, but is introduced into a reaction tube that passes through the light source chamber, and the raw material gas is converted into active species in the reaction tube and introduced into the reaction chamber, thereby forming a film on the substrate. Deposit. In addition, at this time, the part before the gas is introduced into the reaction tube is made into a double-structured tube, and by adopting a structure in which the raw material gas flows through the center and the diluting gas flows toward the inner wall of the reaction tube, N2 is introduced into the reaction tube. Creates a flow condition and prevents film deposition on the inner wall of the reaction tube. Unlike the conventional method of creating a laminar flow state in the reaction chamber, this method uses gas flowing through a thin tube, and the reaction chamber side is in a low pressure state and the gas introduction side is in a high pressure state. Because a fast gas flow occurs from the system side to the reaction chamber side, a stable laminar flow state can be created. Furthermore, even if the reaction chamber becomes larger in order to form a large-area film, this can be handled simply by increasing the number of reaction tubes, so even a large-area film can be formed uniformly.

Examples Examples of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of a photo-CVD apparatus according to an embodiment of the present invention. In addition, the reaction chamber 3, light source chamber 11, and
FIG. 2 shows an exploded perspective view of the gas introduction system A (for source gas) 12 and the gas introduction system B (for diluent gas) 13. However, the diagram regarding the reaction chamber in FIG. 2(a) omits the inside.

In FIG. 1, a raw material gas 7 and a diluent gas 6 are introduced into a reaction tube 1.

At this time, the diluent gas 6 flows along the inner wall side of the reaction tube 1, and the raw material gas flows through the center of the reaction tube 1, maintaining the N flow state and leaving the reaction chamber 3.
reach. At this time, the raw material gas obtains optical energy 9 from the light source 5 on the way and becomes active species to deposit a film on the substrate.

Further, the number of active species generated can be adjusted by changing the height of the light shield 2 of the reaction tube, and the deposition rate can be changed. Furthermore, by making the interior of the light source chamber a mirror surface, the efficiency of supplying light energy can be increased, and by increasing the number of reaction tubes, a film over a large area can be uniformly formed.

Effects of the Invention As described above, the photo-CVD apparatus according to the present invention can prevent a film from being deposited on the light source window, and can uniformly form a film even over a large area. Furthermore, the film deposition rate can be changed by changing the height of the light shield in the reaction tube.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an optical CVD apparatus according to an embodiment of the present invention, and FIG. 2 is an exploded perspective view of each member of the optical CVD apparatus. 1... Reaction tube 2... Light shield 3... Reaction chamber 4... Sample tray 5... Light source 6... Dilution gas 7... Source gas 8...
-Substrate heating heater 9...Light energy lO...Active species 11...Light source chamber 12...Gas introduction system A13...Gas introduction system B

Claims (3)

[Claims] (1) A reaction tube having a structure in which a conduit made of a light-blocking material is connected to at least one end of a conduit made of a light-transmitting material is provided to penetrate the light source chamber, and one end of the reaction tube is connected to a conduit made of a light-shielding material. A light source characterized in that the other end is connected to a gas introduction system on the chamber side, and the light source chamber and the reaction chamber are shielded from light except for a portion where the reaction tube is connected to the reaction chamber. C
VD device. (2) The interior of the reaction tube and the light source are in an airtight state, and raw material gas is flowed into the reaction tube from the gas introduction system to generate active species in the light-transmitting part of the reaction tube. The optical CV according to claim 1, wherein the optical CV is configured to flow into the reaction chamber.
D device. (3) A claim in which the gas introduction system has a double structure at a portion connected to the reaction tube, and is configured to flow the raw material gas into the center of the reaction tube and the diluent gas along the inner wall of the reaction tube. Item 1
The optical CVD apparatus described in .