JPS62123711A - Film forming method - Google Patents

Abstract

PURPOSE:To improve the deposition speed of the film to be deposited on the surface of a base material by a method wherein a plurality of mirrors are provided on the circumferential part of the base material, a light is reflected by the mirrors, the light makes progress repeatedly along the surface of the base material, and a photochemical reaction is performed in the vicinity of the surface of the base material in a highly efficient manner. CONSTITUTION:When a film is going to be formed, the light 4 emitted from a light source 2 is introduced into a chamber 10 from the window 12 provided in the vacuum chamber 10, for example. The light 4 makes progress repeatedly in the vicinity of the surface of the base material along the surface by having the light 4 reflected from a plurality of plane mirrors. As a result, the number of the light 4 passing the part in the vicinity of the surface of the base material 6 can be increased markedly when compared with the method heretofore in use. Consequently, the decomposing reaction of the reactive gas molecule generated in the vicinity of the surface of the base material is increased, and the deposition speed of the film to be deposited on the surface of the base material can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for forming a film by photo-CVD, and particularly to a means for efficiently carrying out a photochemical reaction near the surface of a substrate.

[Conventional technology]

FIGS. 3 and 4 are schematic diagrams showing conventional film forming methods, respectively. In the optical CVD method, for example, an ultraviolet laser (such as a KrF laser) is used as the light source 2. Then, a reactive gas is introduced in advance into a vacuum container (not shown) that houses the base material 6 and is evacuated, and then the light (in this case, ultraviolet laser light) 4 from the light source 2 is used as a base as shown in FIG. Material 6
The light is irradiated parallel to the surface of the base material 6, or as shown in FIG. At that time, the reactive gas molecules obtain the optical energy of the irradiated light 4, causing a decomposition reaction. Alternatively, the surface of the base material 6 is heated by light energy, and the adsorbed molecules undergo a decomposition reaction due to this thermal energy. As a result, a film (
A thin film) is formed.

[Problem that the invention seeks to solve]

However, in the conventional method as described above, the base material 6
There is a problem in that the photochemical reaction cannot be carried out efficiently near the surface of the film, and therefore the deposition rate of the film is extremely low. This is because the absorption coefficients of various gas molecules for the light 4 are extremely small, and in one pass of light under reduced pressure, most of the light energy is not absorbed by the gas molecules.

Therefore, if you try to increase the deposition rate using the conventional method, the amount of light
It is necessary to significantly increase the intensity of the light a2, and if this is attempted, another problem arises for the light a2, etc.

Therefore, an object of the present invention is to provide a film forming method that can efficiently carry out a photochemical reaction near the surface of a base material.

[Means for solving problems]

The film forming method of the present invention is a method of forming a film on the surface of a substrate by a photo-CVD method, in which a plurality of mirrors are provided at the periphery of the substrate, and light is reflected by the mirrors to form a film along the surface of the substrate. It is characterized by repeated progress.

[Effect]

By repeatedly passing the light along the surface of the substrate, the decomposition reaction of reactive gas molecules near the surface of the substrate increases. That is, photochemical reactions are efficiently carried out.

〔Example〕

FIG. 1 is a schematic cross-sectional view showing an example of an apparatus for implementing the film forming method according to the present invention. The method of this invention corresponds to the conventional method shown in FIG.

A base material 6 is housed in a vacuum container 10, and a plurality of plane mirrors 8 are arranged facing inward at appropriate locations around the base material 6. The inside of the vacuum container 10 is evacuated to a vacuum state, and a reactive gas is introduced therein.

When forming a film, the light 4 output from the light source 2 is introduced into the vacuum container 10 through a window (for example, a quartz window) 12 provided in the vacuum container 10, and the light 4 is reflected by a plurality of plane mirrors 8. By doing this, the vicinity of the surface of the base material 6 is repeatedly advanced along the surface (for example, in parallel).

In this case, as the light source 2, for example, the light 4
An ultraviolet laser that outputs ultraviolet laser light as the light 4 or a mercury lamp that outputs ultraviolet light as the light 4 can be used.

In addition, the way the light 4 travels and the number of repetitions are determined by the plane mirror 8.
Various types can be adopted depending on the number and arrangement of the rays, and how the light 4 is incident on them.

According to the method described above, the number of times the light 4 passes near the surface of the base material 6 can be significantly increased compared to the conventional case where it passes once. As a result, the decomposition reaction of reactive gas molecules near the surface of the base material 6 increases. That is, photochemical reactions are efficiently carried out. This allows low power light 4
A high film deposition rate can also be obtained by irradiation of .

Furthermore, by dispersing the route of the light 4 as shown in the figure, for example, the area of the passage of the light 4 on the surface of the base material 6 can be widened, so that a film can be formed over a wide range at a high deposition rate. You can also do that.

In particular, this method has the advantage that, unlike the case of scanning light, there is almost no reduction in the power density of light and the mechanism is simple.

In addition, during film formation, it is preferable to heat the base material 6 with a heater (not shown) or the like, for example, to about 300 to 700"C. By doing so, crystal growth on the surface of the base material 6 is prevented. This is because it can be promoted.

Further, during film formation, the base material 6 may be rotated, for example, in the direction of arrow A in the figure (or vice versa).

In this way, the uniformity of the film quality can be improved.

FIG. 2 is a schematic plan view showing another example of an apparatus for carrying out the film forming method according to the present invention. Illustration of the vacuum container is omitted. Mainly to explain the difference from the embodiment shown in FIG. 1, in this embodiment, two concave mirrors 14 are provided on both sides of the base material 6, and the surface of one concave mirror 14 has a radius of curvature of the other concave mirror 14. It is facing inward so that it is in the center.

When forming a film, for example, light 4 is introduced through a notch 16 provided in one of the concave mirrors 14, and the light is sequentially reflected by both concave mirrors 14 to repeatedly advance near the surface of the base material 6 along the surface. let

In this case as well, the way the light 4 travels and the number of repetitions can be variously selected depending on the radius of curvature of the concave mirror 14, the facing distance between the biconcave mirrors 14, and how the light 4 is made incident thereon. .

Further, heating and rotation of the base material 6 are the same as in the case of FIG. 1.

〔Effect of the invention〕

As described above, according to the present invention, the photochemical reaction near the surface of the base material is efficiently carried out. As a result, the rate of film deposition on the substrate surface is increased without increasing the power of light.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view showing an example of an apparatus for implementing the film forming method according to the present invention. FIG. 2 is a schematic plan view showing another example of an apparatus for carrying out the film forming method according to the present invention. FIGS. 3 and 4 are schematic diagrams showing conventional film forming methods, respectively.

Claims (1)

[Claims] (1) In a method of forming a film on the surface of a substrate using the photo-CVD method, a plurality of mirrors are provided around the periphery of the substrate, and light is reflected by the mirrors so as to travel repeatedly along the surface of the substrate. Characteristic film formation method.