JPS6077413A - Laser excitation process apparatus - Google Patents

Abstract

PURPOSE:To raise reaction speed and significantly improve a film forming speed or etching speed by providing a grid to the laser irradiation part and giving an acceleration voltage to the ion. CONSTITUTION:The laser beam 12 generated by the light source 11 is guided to the reaction chamber 1 through the lens system 13. An ion acceleration grid 14 is provided surrounding the beam path and the side opposite to the substrate 9 is opened. An acceleration voltage up to 50eV is applied by the grid to the ion generated by the laser beam. Thereby the ions are all caused to reach the substrate 9, and other molecules are ionized during such process and moreover, reaction coefficient is increased through promoted reaction at the surface of substrate. The acceleration voltage is set to about 50eV in order to prevent damage of substrate 9. According to this constitution, the laser excitation process can be put into practical use.

Description

[Detailed Description of the Invention] This invention relates to a laser excitation process device that irradiates reactive gas molecules introduced into a reaction chamber with a laser beam such as an excimer laser to ionize them and increase decomposition efficiency. .

Excimer lasers have high energy (e.g. ArF
: 6-42eV, KrF: 5. DeV, XeC
L: 4.02 eV, etc.), it has a high decomposition efficiency when irradiated to molecules, so it is actively used in fields that utilize photochemical reactions. By the way, in the field of semiconductor technology aiming for VLSI, the optical excitation process has been attracting a little attention because it causes less damage to the substrate surface, and CVD using excimer lasers (a method using chemical reactions) has only just begun to be researched. There is. This kind of experimental equipment that has been proposed so far is
As shown in FIG. 1, a gas t is introduced from a gas inlet 4 toward a substrate 3 mounted on a substrate holder 2 inserted in a reaction chamber 1.
It is configured so that a laser beam supplied from an excimer laser device 6 through a lens system 7 is incident through a light introduction window 5 provided on the side wall of the reaction chamber 1, and with this configuration, four people are seated. Molecules existing on the optical path of the laser beam in the reaction chamber 1 are decomposed, and this results in CV
In case D, the substrate 3 will be etched by the radicals deposited on the substrate 6 or generated by decomposition. However, in such a configuration, the reaction on the substrate surface is very slow, and the rate of deposition and etching is very slow.

That is, in CVD and etching using an excimer laser, only excited molecules and radicals are used, and ions are not actively used.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a laser excitation process apparatus configured to actively utilize ions generated by irradiating reaction gas molecules with an excimer laser.

In order to achieve this purpose, the laser excitation process apparatus according to the present invention is configured to provide an ion acceleration grid in the light irradiation section in the reaction chamber and apply an accelerating voltage to the ions to cause an ion-assisted reaction. It is characterized by

The present invention will be further described below with reference to FIGS. 2 and 5 of the accompanying drawings.

FIG. 2.3 shows an embodiment of the laser excitation processing apparatus according to the present invention, in which 8 is a reaction chamber, in which a substrate holder 10 on which a substrate 9 is mounted is rotatably arranged. This reaction chamber is equipped with eight reaction gas inlets 8a, a gas outlet 8b, and a light introduction window 8C. In addition, in Fig. 2, 11 is a laser light source, and this laser light source 1
The laser beam 12 generated in step 1 passes through the lens system 13 and is introduced into the reaction chamber 1 from the light introduction window 8c. An ion acceleration grid 14 is provided along the optical path of the laser beam introduced into the reaction chamber 1 so as to surround this optical path.
The side of the grid 140 facing the substrate 9 is open as shown in FIG. This grid 14 also has a power supply 1
5, a voltage of about 0 to +50V is applied. The ions produced by the laser beam 12 are therefore imparted with kinetic energy by the grid 14 and are given 50e
The light is incident on the substrate 9 with energy up to about V.

As a result, ion assisted etching and CVD are performed. i.e. 50 by grid 14
By applying an accelerating voltage of about eV, all the generated ions can reach the substrate 9, and in the process of reaching them, other molecules can be ionized, and the reaction on the substrate surface can be further promoted. The reaction rate can be increased.

Note that the acceleration voltage is set to 50 eV or less in order to avoid damage caused by scraping.

As explained above, in this invention, an ion acceleration grid is provided at the light irradiation part of the laser beam introduced from the laser light source, and a potential of about 50 eV is applied to the grid to perform ion assisted etching or CVD i. Since the structure is such that the reaction rate can be increased, it is expected that the film formation rate and etching rate will be dramatically increased as a result. This means that the practical application of the l/- laser excitation process, which has hitherto been difficult to put into practical use, is promoted.

Note that an excimer laser is preferably used as the laser light source, but other high-energy lasers with high decomposition efficiency may also be used.

[Brief explanation of drawings]

FIG. 1 is a principle diagram of a conventional laser excitation process device, and FIG. 2 is a schematic diagram of the laser excitation process device of the present invention.
FIG. 6 is a view of the interior of the reaction chamber shown in FIG. 2 as seen from all directions. In the figure, 8: reaction chamber, 11: laser light source. 12: Laser beam, 14: Grid for ion acceleration, 15: Power supply.

Claims (1)

[Claims] In a laser excitation process device that irradiates the reactive gas molecules introduced into the reaction guide with a laser beam to ionize them and increase decomposition efficiency, an ion acceleration grid is provided in the light irradiation section, and an accelerating voltage is applied to the ions to accelerate the ionization. A laser excitation process device characterized in that it is configured to cause an assisted reaction.