JPH0288775A - Laser cvd device - Google Patents

Abstract

PURPOSE:To efficiently form the thin film of a high-melting-point material with high adhesive strength by irradiating a material to be treated by the laser light converged on this side of the material, forming the fine particles of the high melting-point material from the raw gas by pyrolysis, and depositing the particles. CONSTITUTION:A substrate 54 is placed on a substrate holder 52 in a reaction vessel 50. The substrate 54 is irradiated by laser light 66 through an irradiation window 62, and the laser light 66 is converged on a focus 68 on this side of the substrate 54. The raw gas obtained by mixing gaseous SiH4 and gaseous C2H6 is supplied toward the focus 68 through a gaseous mixture nozzle 56. The raw gas is pyrolyzed by the laser light 66 to form fine SiC particles of the high-melting-point material. The formed fine SiC particles are heated by the out-of-focus light, and firmly adhered to the surface of the activated substrate 54 to efficiently form a thin film.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a laser CVD apparatus for forming a thin film of a high melting point material such as ceramic, SiC, SiN, etc. on the surface of a substrate firmly and uniformly. .

[Prior Art] Thin films of high melting point materials such as silicon carbide (S i C) have extremely hard properties, so they can be used for hardening the surface of cutting tool blades and as wear-resistant films for heads. Since it is a good thermally conductive insulator, it can also be used as a heat sink. Furthermore, single crystal films of silicon carbide (S i C) can also be used for manufacturing blue light emitting diodes and heat-resistant ICs.

FIG. 4 is an explanatory diagram showing an example of an apparatus using a conventional laser CVD method for producing ceramic powder by thermally decomposing a mixed gas with laser light.

In the figure, 2 is a substantially cylindrical reaction vessel, 4 and 4 are a pair of opposing laser beam irradiation windows attached to the side wall of the reaction vessel, and 6 is a window projecting upward from the bottom of the reaction vessel 2. 8 is a silane gas supply pipe connected to the base end of the mixed gas nozzle 6; 10 is an ammonia gas supply pipe connected to the base end of the mixed gas nozzle 6 so as to face the silane gas supply pipe 8; Reference numeral 12 denotes a discharge tube provided at the upper part of the reaction vessel 2.

In such a manufacturing apparatus, the inside of the reaction vessel 2 is filled with hydrogen gas (H2), the silane gas supply pipe 8 is supplied with silane gas (SiH4) as shown by the arrow, and the ammonia gas supply pipe 10 is supplied with ammonia gas (NH4). ) are supplied as shown by the arrows, these gases become a mixed gas in the mixed gas nozzle 6, and this mixed gas is ejected into the reaction vessel 2 from the spout at the tip of the mixed gas nozzle 6. In this state, when the laser beam 14 is irradiated into the mixed gas from one side of the laser beam irradiation window 4, the mixed gas instantaneously reacts and decomposes to generate silicon nitride fine particles 16. The generated silicon nitride fine particles 16 are then disposed in the upper discharge pipe 1.
2, and is collected into a collection system (not shown) as shown by arrow A.

Further, FIG. 5 is an explanatory diagram showing another example of an apparatus using the conventional laser CVD method for producing ceramic powder by thermally decomposing a mixed gas with laser light.

In the figure, 18 is a reaction vessel, 20 is a laser beam irradiation window formed on the side of this reaction vessel, 22 is a Zn5e lens attached to the outside of this laser beam irradiation window, and 24 is a laser beam irradiation window 20. 26 is a KCl window 24 installed inside the reaction vessel 18.
28 is a silane gas supply pipe connected to the side of this quartz tube, and 30 is a quartz tube 26 similar to this silane gas supply pipe.
32 is also an Ar gas supply pipe connected to the side of the quartz tube 26 like the silane gas supply pipe; The body 36 is an opening formed in the side of the reaction vessel 18 at a position opposite to the laser beam irradiation window 20.

In such a manufacturing apparatus, silane gas (SiH4) is supplied to the silane gas supply pipe 28, ethylene gas (C2H4) is supplied to the ethylene supply pipe 30, and Ar is supplied to the Ar gas supply pipe 32.
When each gas is supplied, these gases become a mixed gas in the quartz tube 26. In this state, when the laser beam 40 is coaxially irradiated into the quartz tube 26 through the Zn5e lens 22, the irradiation window 20, and the KCI window 24, the mixed gas is thermally decomposed and Si-based ceramic powder is generated.

In addition to the laser CVD method described above, there are also ceramic film forming methods that do not use laser light: a: ultraviolet CVD that applies photochemical reactions, b: plasma CVD that uses plasma energy, or C: that uses discharge energy. Methods such as discharge CVD are also known.

[Problems to be Solved by the Invention] However, although the manufacturing apparatuses shown in FIGS. 4 and 5 described above can synthesize ceramic powder, they cannot generate a ceramic film. In addition, the above-mentioned method a does not use a laser.

The ceramic film forming methods b and c are relatively gentle synthesis methods and are not known as methods for producing thin films of high melting point materials.

The present invention was made in order to solve this problem, and an object of the present invention is to obtain a laser CVD apparatus that can efficiently obtain a thin film of a high melting point material.

[Means for Solving the Problems] A laser CVD apparatus according to the present invention includes a reaction vessel that houses and holds a workpiece, a laser beam irradiation means that irradiates the workpiece with a laser beam, and a laser CVD apparatus that includes The above problem has been solved by having a laser beam focusing means for focusing the laser beam in front of the object to be processed, and a raw material gas supply means for supplying a raw material gas for thermally decomposing fine particles of a high melting point material using the focused laser light. It is something.

[Function] In the present invention, the surface of the object to be treated is irradiated with laser light so as to be focused in front of the object,
Since a raw material gas that generates fine particles of a high melting point material by thermal decomposition is supplied near the surface of this workpiece, the raw material gas is thermally decomposed near the surface of this workpiece to generate fine particles of a high melting point material, Furthermore, since the surface of the object to be treated is heated by laser light, the generated fine particles of the high melting point material are firmly deposited and adhered to the surface of the object in the form of a film.

[Example] FIG. 1 is an explanatory diagram showing an example of the laser CVD method of the present invention.

In the figure, 50 is a reaction container, 52 is a table-like substrate holder installed at the bottom of this reaction container, 54 is a substrate as a processing object attached to this substrate boulder, and 56 is a reaction container. 58 is a silane gas supply pipe connected to the base end of the mixed gas nozzle, and 60 is the base end of the mixed gas nozzle 56, similar to the silane gas supply pipe 58. an ethylene gas supply pipe 62 connected to the reaction vessel 50;
an irradiation window provided above the substrate 54, that is, directly above the substrate 54;
Reference numeral 64 indicates an exhaust pipe provided at the bottom of the reaction vessel 50 to avoid the feet of the substrate holder 52, reference numeral 66 indicates a laser beam that is irradiated onto the substrate through an irradiation window, and reference numeral 68 indicates a focus of this laser beam. A focal point 68 of the laser beam 66 is set at a height of about several mm above the substrate 54.

When silane gas (SiH4) is supplied to the silane gas supply pipe 58 and ethylene gas (C2H4) is supplied to the ethylene gas supply pipe 6°, these gases are mixed in the mixed gas nozzle 56, and are discharged from the tip of the mixed gas nozzle 56 to the substrate 54. is supplied near the surface. When laser light 66 is irradiated onto the surface of the substrate 54 through the laser light irradiation window 62, this laser light is focused and
The surface of the substrate 54 is further heated. Silane gas (S i H) and ethylene gas (C
2H4) is the focal point 6 of the laser beam 66.
8, it is heated and decomposed as shown in the chemical reaction formula below to produce fine particles of silicon carbide (S i C), and
Fine particles of silicon carbide (S i C) generated by this decomposition are deposited and attached to the surface of the substrate 54 in the form of a film.

2SIH4+C2H4→2 S IC+ 6 H2 At this time, since the substrate 54 located below the focal point 68 is heated and heated by the slightly expanded laser beam 66 and becomes an activated surface, the generated silicon carbide (Si The fine particles of C) form a film and are firmly deposited and adhered to the surface of the substrate.

FIG. 2 is an enlarged perspective view of the vicinity of the focal point of the laser beam 66 shown in FIG. 1.

In the same figure, when fine particles of silicon carbide (S i C) are deposited and attached to the surface of the substrate 54 in the form of a film, the substrate holder (not shown) is moved at an appropriate speed By moving in the force direction, the same film surface can be obtained over a wide area on the surface of the substrate 54.

FIG. 3 is a perspective view showing an example in which a cylindrical lens is used as means for focusing the laser beam 66 shown in FIG. 1.

In the same figure, since the laser beam 66 is focused into a slit shape by a cylindrical lens (not shown), if the substrate holder (not shown) is moved in the x and y direction at an appropriate speed in this state, a wide area can be formed on the surface of the substrate 54. Membranes can be obtained faster.

It goes without saying that the focus position must be appropriately adjusted depending on the type of substrate, the type of gas, the flow rate, the laser power, the wavelength, the focal length of the condensing lens, etc.

The thin film of the high melting point material obtained in this way can be used for SiC diodes (blue light emitting diodes), high temperature resistant ICs (approximately 50%
0°C), head wear-resistant film, heat sink or SOI
It can be used for etc.

[Effects of the Invention] The present invention focuses the laser beam not on the surface of the workpiece, but
Since the connection is made at a height slightly away from the surface, the raw material gas is thermally decomposed just before the surface of the object to be processed and particles of high melting point material are generated, and the generated particles of high melting point material are immediately released. It is efficiently deposited in the form of a film on the object to be processed, and the surface of the object to be processed is also heated and activated by the out-of-focus light, so the generated particles of high melting point material adhere firmly. There is an effect.

In addition, since the present invention uses laser light, the temperature becomes high only near the focal point, and the container, jig, etc. are not heated, so there is no possibility that the thin film from the container, jig, etc. will be contaminated.
This has the advantage that a thin film of a high-melting point material with high purity can be obtained.

Furthermore, since the present invention uses laser light to efficiently decompose the raw material gas, there is also the effect that CVD can be performed at a relatively low temperature in the entire apparatus.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing one embodiment of the present invention, and FIG.
An enlarged perspective view showing the vicinity of the focal point of the laser beam 66 shown in the figure;
FIG. 3 is a perspective view showing another example of the focused state of the laser beam shown in FIG. 1, and FIGS. 4 and 5 are explanatory diagrams showing the conventional CVD method. 50-... Reaction container, 52... Substrate holter 54... Substrate, 56-... Mixed gas nozzle, 58... Silane gas supply pipe, 60 ...
・-・Ethylene gas supply pipe, 62・・・・laser light irradiation window, 64・・・exhaust pipe, 66・・・・−
Laser light, 68...--Focus. Patent applicant Kunio Kakiki, Representative of Victor Japan Co., Ltd.

Claims (1)

[Claims] A reaction vessel that stores and holds a workpiece, a laser beam irradiation means that irradiates the workpiece with a laser beam, a laser beam focusing means that focuses the laser beam in front of the workpiece, and a laser beam focusing means that focuses the laser beam in front of the workpiece. A laser CVD apparatus comprising a source gas supply means for supplying a source gas for thermally decomposing fine particles of a high melting point material using a laser beam.