JPS62116775A - Plasma cvd device - Google Patents

Abstract

PURPOSE:To improve energy application and th rate of forming thin films by using a cavity resonator having a movable short-circuiting plate for plasma generation. CONSTITUTION:The cavity resonator 2 is used for plasma generation. A non-film forming gas is converted to plasma when the non-film forming gas is introduced into the cavity resonator 2 and microwaves are applied thereto. The plasma is released from the cavity resonator 2. The electrons in the plasma are accelerated by the diverging magnetic field of a ceramic coil 3 and is directed toward a substrate 9. A film forming gas is decomposed by contacting the activated plasma when the film forming gas is supplied just before the substrate 9; at the same time, the film forming gas collides against the substrate 9 and deposits the thin film on the substrate 9. The impedance matching of a waveguide 6 for the microwaves and the cavity resonator 2 is controlled to an optimum state at all times by vertically moving the short-circuiting plate 4 of the cavity resonator 2. The reaction conditions of a plasma CVD device are thereby adjusted to the optimum conditions.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a CVD (chemical vapor deposition) apparatus used for forming thin films, and particularly to a plasma CVD apparatus.

In this specification, particles include radicals, ions, and
, molecules, ultrafine particles, and other excited active species. In addition, a beam refers to a jet having a substantially constant cross-sectional area in the flow direction, and its cross-sectional shape is not limited.

[Conventional technology] High-frequency plasma CVD, which has been conventionally used for thin film formation
The device feeds a film-forming gas (raw material gas), which is the source of a thin film, into a reaction chamber, creates plasma by high-frequency discharge, decomposes the film-forming gas, and applies activation energy to the substrate placed in the reaction chamber. It formed a thin film on the surface.

[Problems to be Solved by the Invention] However, in the conventional device, due to the structure L of the device, energy generated by high frequency discharge could not be used efficiently. For this reason, the rate of thin film formation on the substrate 1 was poor, and external heating was required. Furthermore, since the film-forming reaction is carried out in a plasma atmosphere, there is a drawback that an unnecessary film is also deposited on the inner wall surface of the reaction chamber.

SUMMARY OF THE INVENTION An object of the present invention is to provide a plasma CVD apparatus that uses energy more efficiently and improves the thin film production rate.

[L stage for solving problems] The present invention is a plasma CVD apparatus that uses a cavity resonator with a movable shorting plate to generate plasma.

In the present invention, a resonator is a waveguide whose both ends are short-circuited with a conductor, and by applying microwaves through a quartz plate, the inside becomes resonant and plasma is generated. This is what I did. In the cavity resonator used in the present invention, one of the shorting plates is movable and the internal capacitance is variable, so that impedance matching can be achieved. Further, a non-film-forming gas that becomes plasma is sent into the cavity resonator, and a film-forming gas that becomes a reaction gas is supplied near the outlet of the cavity resonator.

[Function] The non-film forming gas that is sequentially fed into the cavity resonator is excited by the microwave and becomes plasma. When this plasma gas is discharged from the outlet, a film forming gas is supplied from the vicinity of the cavity resonator outlet. As a result, the film-forming gas comes into contact with the activated plasma gas and is decomposed, and when it reaches the substrate, the particles of this film-forming gas recombine on the substrate, depositing a thin film.

[Example] FIG. 1 is a schematic diagram of a plasma CVD apparatus showing an example of the present invention. In the figure, l is a plasma CVD device, 2
3 is a cavity resonator, 3 is a magnetic coil serving as a magnetic field generator, and 9 is a base body.

In FIG. 1, a non-film forming gas supply pipe 7 is provided in the cavity resonator 2.
is provided, and a magnetic coil 3 is arranged near the outlet,
A film forming gas supply pipe 8 is provided between the magnetic coil 3 and the base 9. On the other hand, the microwave is carried by the waveguide 6 and sent into the cavity resonator z via the quartz plate 5.

The magnetic field generator in this embodiment is a magnetic coil excited by an external power source, but a permanent magnet or the like may also be used. This magnetic coil is used to draw out the plasma generated within the cavity resonator 2 using a divergent magnetic field.

Further, the shorting plate 4 of the air conditioning resonator in this embodiment has a choke structure as shown in the figure.

This is because when the shorting plate 4 is made movable, a wall current flows through the connection between the shorting plate 4 and the cavity resonator 2.

This is because the loss increases, and by using such a choke structure, the loss due to the wall current can be minimized.

In the above configuration, when the non-film forming gas is sent into the cavity resonator 2 and the microwave is changed, the non-film forming gas becomes plasma and is emitted from the cavity resonator 2. Electrons in this plasma are accelerated by the divergent magnetic field of the magnetic coil 3 and move toward the substrate. Along with this movement of electrons, ions are also dragged toward the substrate. At this time, when a film-forming gas is supplied from just before the substrate, the film-forming gas comes into contact with the activated plasma gas and decomposes. At the same time, the film forming gas collides with the substrate 9 together with the plasma gas. The decomposed film-forming gas is recombined on this substrate and deposited as a thin film.

In the above embodiment, by moving the shorting plate 4 of the cavity resonator 2 up and down, the impedance matching between the waveguide and the cavity resonator is always controlled to be in the optimum state.

[Effects of the Invention] As explained above, according to the present invention, by using a cavity resonator as a plasma generation chamber, it is possible to efficiently change the energy of microwaves, and to generate heat at low temperatures without applying heat from the outside. Film production can be performed. Also,
Since the film forming gas is supplied just before the substrate, more particles (radicals, ions, atoms, molecules, etc.) can be collected on the substrate.

In particular, in the cavity resonator according to the present invention, since the shorting plate is movable, the impedance matching between the waveguide and the cavity resonator can be easily adjusted, and the reaction conditions are always adjusted to the optimum state. be able to.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of an apparatus showing an embodiment of the present invention. 2... Cavity resonator, 3... Magnetic coil, 4... Short circuit plate, 6... Waveguide, 9... Substrate.

Claims (1)

[Claims] 1) A plasma CVD apparatus characterized by having a cavity resonator with an adjustable shorting plate.