JPS61174943A - Laser cvd device - Google Patents

Abstract

PURPOSE:To increase the utilizing efficiency of laser beam by providing oppositely at least one couple of reflecting mirrors which reflect multiply the laser beam being made incident from an incident port in the inside of a reaction chamber having the incident port of laser beam. CONSTITUTION:The laser beam 11 generated in a laser oscillator 1 is introduced into the inside of the reaction chamber 2 through the incident port 5 of laser beam and reflected by a reflecting mirror 13. The reflected laser beam 11 is rereflected by a reflecting mirror 14 provided to the reflecting side of the reflecting mirror 13. While the laser beam introduced from one side of the reaction chamber 2 is reflected in the chamber 2 by this repeat, it reaches the outlet 6 of laser beam diagonal to the incident port 5. Therefor the optical path of laser beam in the chamber 2 is made long and the excitation of the reaction gas is efficiently performed by the increase of the collision against a reaction vessel in the reaction chamber or the increase of contact time.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is directed to a laser CV that improves the utilization efficiency of laser light.
D (Chemical Vapor Deposition) Apparatus.

Conventional technology The formation of CVD films is required in the production of semiconductor devices, especially semiconductor integrated circuits, and laser CVD, which uses laser light, is used as a secondary device for forming CVD films.
The device is now in use.

FIG. 3 shows an example of the configuration of a conventional laser CVD apparatus that avoids direct irradiation of the substrate with laser light, irradiates the substrate with laser light in parallel, and uses both photo-induced reaction and thermal decomposition. 1, its basic configuration consists of a laser oscillator 1 and a reaction chamber 2. Note that a substrate heating table 3 is installed in the reaction chamber, and a reaction gas inlet 4. Laser light incidence b6. A laser beam outlet 6 and a reaction gas discharge lower are formed, and a heater 8 is attached to the substrate heating table 3, and the heating operation is controlled by a substrate temperature controller 9. By the way, the condensing lens 10 disposed between the laser oscillator 1 and the laser beam entrance 6 is for condensing the laser beam 11, and acts to increase the power density per unit area.

Substrate 12 on which a CVD film is to be formed, such as a semiconductor wafer
is placed on the substrate heating table 3, and a CVD film is formed in this state. That is, a CVD film is formed on the main surface of the substrate 12 by excitation of a reactive gas and promotion of a chemical reaction by the laser light 11 which is parallel to the main surface.

Problems to be Solved by the Invention When a photoinduced reaction is generated using the laser CVD apparatus described above, the laser beam only passes over the surface of the substrate 12, and its contribution to the reaction is low. Furthermore, since the reaction gas is excited only in the area irradiated with laser light, it is difficult to form a uniform film over the entire surface of the substrate or over a relatively wide surface area.

The present invention aims to realize a laser CVD device that can irradiate the entire area in a reaction chamber with laser light, increase the efficiency of using laser light for photoexcitation reactions, and make it possible to form a uniform CVD film. .

Means for Solving the Problems The laser CVD apparatus according to the present invention includes at least one pair of reflectors that multiple-reflects the laser beam incident from the laser beam entrance into the interior of the reaction chamber having the laser beam entrance. Mirrors are installed facing each other, and the optical path of the laser beam that is multiple-reflected within the reaction chamber between the mirrors is configured so that it can cover the main surface of the substrate that is installed parallel to the laser beam. ing.

By installing a reflector to reflect the laser beam in the reaction chamber and lengthening the optical path of the laser beam within the reaction chamber, the contribution rate of the laser beam to the photo-induced reaction is increased. As a result, the formation speed of the thin film becomes faster and the uniformity of the film thickness and film quality increases.

Embodiment FIG. 1 is a perspective view schematically showing a configuration example of a laser CVD apparatus according to the present invention, and FIG. 2 is a schematic diagram showing the progress state of laser light in a reaction chamber.

As shown in FIG. 1, in the laser CVD apparatus of the present invention, reflecting mirrors 13 and 14 for multiple reflection of the laser beam 11 are installed facing each other inside a reaction chamber 2 for forming a thin film on the surface of a substrate. ing. Laser light 11 generated by laser oscillator 1 is introduced into reaction chamber 2 through laser light entrance 5 and reflected by reflecting mirror 13 . Further, the laser beam 11 reflected here is reflected again by a reflecting mirror 14 installed on the opposite side of the reflecting mirror 13. By repeating this nine times, the laser beam introduced from one corner of the reaction chamber 2 reaches the laser beam outlet 6 located diagonally to the laser beam entrance 5 while being reflected within the reaction chamber. For this reason, the optical path of the laser beam in the reaction chamber becomes longer, resulting in an increase in collisions with the reaction chamber in the reaction chamber or an increase in contact time.
Excitation of the reaction gas is done efficiently.

FIG. 2 two-dimensionally shows the state of multiple reflection of the laser beam described above. It reaches the laser light outlet 6 by scanning upward.

In order to effectively perform such multiple reflections, consideration may be taken such as tilting the direction in which the laser beam 11 is introduced into the reaction chamber, or tilting the reflecting mirror, as shown in the figure.

Effects of the Invention In the laser CVD apparatus of the present invention, the optical path of the laser beam within the reaction chamber is significantly lengthened, the reaction gas within the reaction chamber is efficiently excited, and the photoinduced reaction is promoted over a wide range. Therefore, it is possible to form a film over a wide range within the reaction chamber, and the time required to form a CVD film over the entire substrate is shortened. Furthermore, the effect of making the thickness and quality of the CVD film formed on the substrate uniform is achieved, and when this substrate is a semiconductor substrate, the characteristics of the semiconductor device are improved.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an example of the configuration of the laser CVD apparatus of the present invention, FIG. 2 is a schematic diagram showing the progress state of laser light in a reaction chamber, and FIG. 3 is a diagram showing the configuration of a conventional laser CVD apparatus. be. 1...Laser oscillator, 2...Reaction chamber, 3...Substrate heating table, 4...Reaction gas inlet, 6...Laser Light entrance port, 6...
・Laser light outlet, end... Reaction gas outlet, 8
... Heater, 9 ... Substrate temperature controller, 10 ... Condensing lens, 11 ...
Laser light, 12...Substrate, 13.14...
··Reflector. Name of agent: Patent attorney Toshio Nakao and 1 other person3-
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Claims (1)

[Claims] Inside a reaction chamber having a laser beam entrance, at least one pair of reflecting mirrors that multiple-reflect the laser beam incident from the said entrance are installed facing each other, and within the reaction chamber between the reflecting mirrors, A laser CVD apparatus characterized in that the optical path of the multiple reflected laser beam is set such that the main surface of a substrate placed parallel to the laser beam can be coated.