JPS63153278A - Thin film forming device - Google Patents

Abstract

PURPOSE:To permit control to excellent film quality at a high speed by using a UV laser oscillator to dissociate film forming gases and using an electron cyclotron resonance plasma generator to generate ions for controlling film formation process. CONSTITUTION:The film forming gases in a reaction chamber 5 are photodissociated by two-photon absorption of UV laser light 2. The hydrogen ions in a plasma forming chamber 8 are given an adequate speed by a meshed electrode 12 for ion acceleration and arrive at the surface of a substrate 6. The hydrogen ions collide against the surface of the substrate 6 at the initial period of the film formation to facilitate crystal distortion so that the nucleus of diamond or the like is easily grown. An etching effect is intensified to suppress the growth of a graphite crystal when energy is applied to the hydrogen ions in the ensuing process. The plasma density is increased by the electron cyclotron resonance plasma generator 8 constituted of the plasma forming chamber 8, an air core coil 9 and microwave 10 generating source, by which the film formation process is executed at the high speed with good controllability.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a thin film forming apparatus using a laser, for example, by depositing a high purity diamond thin film or cubic boron nitride thin film with thermal conductivity and electrical insulation on a substrate. The present invention relates to an apparatus for forming films at high speed while controlling film quality while maintaining the average temperature at approximately room temperature.

[Conventional technology]

In order to put thin film formation technology into practical use, it is desirable to lower the temperature of the thin film formation process in order to avoid the adverse effects of heat on the substrate, and at the same time, a high speed thin film formation technology is desired in order to reduce manufacturing costs. There is.

As a new technology to meet this demand, a so-called laser CVD technology has been proposed in which a film-forming gas is photodissociated using the high photon energy of ultraviolet laser light to form a thin film. This technology can dissociate gas using only high photon energy, so it has the excellent feature of being able to quickly deposit reaction products on the substrate at low temperatures. It has been difficult to stably obtain a film of good quality because there is no mechanism for controlling the composition of the reaction product or for separately performing the process in which the reaction product forms an F4 film on the substrate.

FIG. 2 shows, for example, a publication (Applied Physic
s Leffers Vol. 43 No. 5 No. 454-45
Conventional laser CV using a laser, shown on page 6)
FIG. 3 is a cross-sectional configuration diagram showing the D device.

In the figure, (1) is an ultraviolet laser oscillator, (2) is an ultraviolet laser beam, (3) is a cylindrical telescope for shaping the ultraviolet laser beam (2) to the energy density required for dissociation of the film-forming gas, (4) The ultraviolet laser beam (2) is transmitted to the reaction chamber (
5) Quind for introduction into (sr)FiIl
ilj membrane gas supply port, (52) Vi its discharge port,
(6) is a substrate % (7) is a susceptor with a heater for heating the substrate (6).

Ultraviolet laser light (
2) Iri is shaped by the cylindrical telescope (3) to an appropriate energy density for the dissociation of the film-forming gas, and passed through the quind (4) to tc11! A gas atmosphere for I is introduced into the reaction chamber (5). Ultraviolet laser light (2) is installed in the Fi reaction chamber (5) and nine substrates (
6) in parallel to the substrate (6) to dissociate the film-forming gas.

The reaction product obtained by this dissociation reaction is deposited on the substrate (6) according to Buddhism.

However, depending on the type of film forming gas, PII#:t, which is composed of reaction products generated by dissociation of film gas due to high photon energy, may contain impurities or have problems such as crystallinity not being as expected. was there.

Therefore, in the conventional apparatus shown in FIG. 2, the surface of the substrate is heated to several hundred degrees Celsius by a susceptor equipped with a heater to control the quality of the film deposited on the substrate.

[Problem that the invention seeks to solve]

Conventional laser thin film forming equipment produces reaction products! Since it does not have an IJaJ mechanism, it has been difficult to obtain the expected film quality. Furthermore, in order to control the quality of the film, the only method found was to heat the substrate to several hundred degrees, making it impossible to control the quality of the film at low temperatures.

This invention was made to solve the above-mentioned problems, and it controls the film process when forming a thin film at low temperature and at high speed by utilizing film-forming gas dissociation using high photon energy. The purpose is to provide a thin film forming apparatus that can obtain the expected film forming quality.

[Means for solving problems]

The W# film forming apparatus of the present invention includes a reaction chamber that accommodates a substrate and is filled with a film-forming gas, an ultraviolet laser oscillator that oscillates an ultraviolet laser beam that dissociates the film-forming gas and forms a thin film on the substrate, and It is equipped with an electron cyclotonic resonance plasma generator that generates ions for controlling the film-forming process.

[Operation] In this invention, the film-forming gas and the tL film-protection process control gas are configured as separate systems, and the former is treated with ultraviolet laser light, and the latter is treated with electron cyclotron resonance plasma generation. Equipment (BCR (Electron Cyc)
A promising thin film is obtained by turning the TC film into plasma using a LOTON REAONANCE (abbreviated as "plasma generator") and applying the dissociated TC film gas to the surface of the substrate.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings, targeting diamond thin film formation. FIG. 1 is a sectional view showing a thin film forming apparatus according to an embodiment of the present invention. In the figure, (1) is an ultraviolet laser oscillator, (2) is an RRI ultraviolet laser beam, (3) is a cylindrical telescope,
(4) Kequind, (5) #- reaction chamber, (6)
is a substrate, (7) is a susceptor that holds the substrate (6), (8
) is the plasma generation chamber of the ECR plasma generator, (9)
is the air-core coil for magnetic field generation, (10) #-i microwave (2, 45CH2), ECR plasma generator is pu, i' sma generation chamber (8), air-core coil (9) microf! 1 (10) t-generating microwave source (not shown)
Consisted of. (ll) Fi hydrogen plasma,
(12) Mesh electrode for accelerating i ions, (51) Supply port for supplying film-forming gas C) i4, (52) Exhaust port on the R vacuum pump side, (53) ECR7" plasma source gas H
This is the supply port for introducing 2.

Methane (CH4) film-forming gas (several tens of Torr) in the repulsion chamber (5) Ultraviolet laser light (2 ) (peak output: 10 μm/d ) and is photodissociated by two-photon absorption. On the other hand, the hydrogen plasma in the plasma generation chamber (8), that is, hydrogen ions, is generated by the ion acceleration mesh i1! pole (1
2), the substrate inside the chamber (
6) Reach the surface. During the initial process of film formation, these hydrogen ions collide with the substrate surface to form crystal distortions, facilitating the formation of nuclei for diamond crystal growth. In the process after nucleation, when hydrogen ions are given an energy of 100 eV,
The etching effect becomes stronger and works to suppress graphite crystal growth that occurs at the same time as diamond crystal growth. Therefore, a diamond thin film with the expected film quality and no impurities can be obtained. Furthermore, since the ECR plasma generator can increase the plasma density by one order of magnitude or more than a normal plasma device, it is possible to perform these riLs processes at high speed and with good control. Furthermore, this film formation process can be performed without heating the substrate while maintaining it at approximately room temperature.

2. In the above example, in the case of forming a diamond thin film -
However, it can also be applied to other thin all formations. For example, a mixed gas of N2 and N2 as the plasma source gas species;
If B2H is used as the gas species flowing into the reaction chamber, a cubic boron nitride film of excellent film quality can be obtained at high speed while maintaining the temperature at approximately room temperature, as in the above embodiment.

c Effects of the Invention J As described above, according to the present invention, a reaction chamber containing a substrate and filled with a film-forming gas emits an ultraviolet laser beam that dissociates the film-forming gas and forms a thin film on the substrate. By using a device equipped with an ultraviolet laser oscillator that generates ion beams, and an electron cyclotron resonance plasma generator that generates ions that can control the film-reflecting process, it is possible to control the growth of specific crystal nuclei and the suppression of undesirable crystal nuclei, thereby improving film quality. This has the effect of providing a thin film forming apparatus that can easily control the temperature and form a film of excellent quality at high speed while maintaining the substrate at approximately room temperature.

[Brief explanation of the drawing]

FIG. 1 shows a cross section of a laser thin film forming apparatus according to an embodiment of the present invention.The second factor is a conventional laser 41! I! FIG. 2 is a cross-sectional configuration diagram showing a forming apparatus. In the figure, (υ is an ultraviolet laser oscillator, (2) is an ultraviolet laser beam, (5) is a Fi reaction chamber, (51) is a film-forming gas supply port, (6) is a substrate, (8) is a plasma generation chamber, (9) r/i air-core coil, (10) H microwave. In this case, the ECR plasma generator is a plasma generation chamber (
8), an air-core coil (9), and a microphone Oi (10) source. In addition, in FIG. 1, the same reference numerals indicate the same or corresponding parts.

Claims (2)

[Claims] (1) A reaction chamber containing a substrate and filled with a film-forming gas, an ultraviolet laser oscillator that oscillates an ultraviolet laser beam that dissociates the film-forming gas and forms a thin film on the substrate, and ions for controlling the film-forming process. A thin film forming device equipped with an electron cyclotron resonance plasma generator that generates (2) The thin film forming apparatus according to claim 1, wherein the ions for controlling the film forming process are accelerated by a mesh electrode for ion acceleration.