JPH073632Y2 - Laser CVD equipment - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention irradiates a laser CVD apparatus, that is, a semiconductor wafer or a glass mask with a laser beam to give active energy to the reaction gas flowing on the surface to decompose it. The present invention relates to a laser CVD apparatus that forms a thin film on the surface by using molecules.

[Conventional technology]

Conventionally, in this laser CVD apparatus, in order to determine the shape of the thin film to be formed, an XY slit with a variable aperture is provided between the objective lens and the laser oscillator, this slit is adjusted according to the object, and the objective is fixed. A method of reducing the slit image with a lens and irradiating it on the substrate is used.

[Problems to be solved by the device]

In this conventional method, there is a problem that the unevenness of the transverse mode distribution of the laser causes a partial unevenness of the film thickness, and the difference in heat conduction causes the film thickness around the thin film to increase compared to the central part. Occurs.

What has been caused by the distribution of the transverse mode of the laser can be averaged to some extent by scanning the laser light by using a vibrating mirror or the like immediately before the variable slit.

However, as shown in FIGS. 3 (a) to 3 (d), since the heat conduction is good in the peripheral portion of the film as shown in the time course, even if the density of the laser light to be irradiated is made uniform, the film is smaller than that in the center. The problem remains that the thickness grows faster and the thickness of the peripheral portion 91 of the thin film is larger than that of the central portion 92.

The present invention is intended to solve such a problem of the conventional one, and it is possible to obtain a uniform film thickness which is almost the same as that of the central portion by suppressing the swelling of the peripheral portion of the grown thin film. Is provided.

[Means for Solving the Problems]

According to the present invention, the shape of a solid thin film is determined in a laser CVD apparatus in which a reaction gas is caused to flow on a substrate such as a semiconductor wafer or a glass mask and a laser beam is irradiated to cause a chemical reaction in the reaction gas to deposit a solid thin film. Therefore, a laser CVD apparatus is provided which has a means for gradually expanding the opening of the variable slit provided in the passage of the laser light in a sequence during laser irradiation.

〔Example〕

 Next, the present invention will be described with reference to the drawings.

FIG. 1 is a schematic view of the configuration of an embodiment of the present invention. Laser light emitted from a laser light source 1 that oscillates ultraviolet light first enters a variable aperture slit 3 via a shutter 2. Here, the laser light passes only through the opening, and the reaction gas 7 passes through the lens 4.
Is condensed on the surface of the sample 5 in the chamber 6.

At this time, when the positions of the variable aperture slit 3 and the lens 4 are adjusted so that the image of the variable aperture slit 3 is formed on the surface of the sample 5, a shape similar to the slit image is obtained.
The CVD film 9 can be formed.

In the above case, the opening operation of the variable opening slit 3 is controlled by the slit opening controller 8. The slit aperture controller 8 here opens and closes the variable aperture slit 3 and adjusts the size thereof, and then, as shown in FIGS. 2A to 2D, the aperture diameter of the slit is set as a target film. Control is performed by changing it with time according to a sequence according to the thickness, the surrounding shape, the material of the substrate, and the like. For example, from (a) to (d), the opening of the slit is gradually expanded in four steps to obtain the target size and film thickness of (d).

[Effect of device]

As described above, according to the present invention, by changing the opening of the variable slit during laser irradiation, it is possible to suppress the rise around the grown thin film and obtain a uniform film thickness that is almost the same as the central part. This has the effect of preventing problems in stacking and post-processing, and controlling growth (mainly by thermal CVD) due to wraparound to unnecessary parts.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an embodiment of the present invention, and FIG. 2 (a).
~ (D) is a diagram showing the relationship between the growth of the film and the opening of the slit during the CVD in the present invention over time, Fig. 3 (a) ~.
(D) is a diagram showing the relationship between the growth of the CVD film by the conventional method and the opening of the slit with time. Explanation of symbols: 1 is laser light source, 2 is shutter, 3 is variable aperture slit, 4 is lens, 5 is sample, 6 is chamber, 7 is reaction gas, 8
Is a slit aperture controller, and 9 is a CVD film.

Claims (1)

[Scope of utility model registration request] 1. In a laser CVD apparatus in which a reaction gas is flown onto a substrate to irradiate a laser beam to cause a chemical reaction in the reaction gas to deposit a solid thin film, a laser beam of a laser beam is used to determine the shape of the solid thin film. A laser CVD apparatus having means for gradually expanding the opening of a variable slit provided in a passage according to a sequence during laser irradiation.