JPH0361370A - Thin film forming device - Google Patents

Abstract

PURPOSE:To form a good-quality thin film at a high rate by activating a reaction product with the ion electron in microwave plasma produced in an ionization chamber and further with the RF plasma produced below the chamber. CONSTITUTION:A raw gas is introduced into a vacuum vessel 1 in which a substrate holder 2 holding a substrate 3 is set. A microwave power 7 and a magnetic field 10 are impressed on the ionization chamber 5 above the vessel 1 to produce plasma. A power 8 is simultaneously impressed on an RF coil 4 to produce RF plasma. Consequently, the reaction product in the plasma produced in the chamber 5 is further activated to grow a film on the substrate 3.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an apparatus for forming high-quality thin films.

[Conventional technology]

Conventionally, the CVD method is already well known, in which a gas is introduced and a gas reactant activated by RF plasma or a gas reactant activated by microwave plasma is deposited on a substrate.

[Problem to be solved by the invention] By the way, with RF plasma alone, the ionization in the gas is low and the amount of radicals is also low, so it is not possible to obtain a sufficient deposition rate unless the pressure horn in the chamber is increased to increase the amount of radicals. However, when synthesizing a film over a large area, it is difficult to generate plasma and it tends to become unstable. On the other hand, when the gas pressure is high using microwave plasma alone, the area of the generated plasma is narrow, so it is not possible to synthesize a film over a wide area. However, although a film can be synthesized over a relatively wide area outside the ionization chamber, the ionization in the plasma at that location is not high and the amount of radicals is small.

An object of the present invention is to provide an apparatus that can form a high-quality thin film at high speed by generating microwave plasma in an ionization chamber and simultaneously promoting gas activation using RF plasma. be.

[Means for Solving the Problems] In order to achieve the above object, the thin film type device according to the present invention includes a vacuum chamber in which a substrate holder for holding a substrate is installed, and a plasma generated by the action of microwaves and a magnetic field. and an RF coil that generates RF plasma and activates reaction products in the plasma that are generated in the ionization chamber and act on the substrate in the vacuum chamber.

[Function] In the present invention, products reacted by ions and electrons in the microwave plasma generated in the ionization chamber provided at the top of the vacuum chamber are generated by the RF coil electrode installed below. Since activation can be further enhanced by the generated plasma, thin films can be formed with high quality and at high speed.

[Example 1 Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, an ionization chamber 5 is installed above a vacuum chamber l having a degassing port 16, and the vacuum chamber I and the ionization chamber 5 are connected through a quartz tube 13. There is a heater 1 inside the vacuum chamber 1.
A substrate holder 2 containing a substrate 5 is installed, and a substrate 3 is mounted facing the quartz tube 13 communicating with the ionization chamber 5. 14 is an AC power source for heating the heater I5. An RF coil 4 for generating RF plasma is installed in the quartz tube 13 communicating with the vacuum chamber 1. Reference numeral 8 denotes an RF power source that energizes the RF coil 4.

A magnet 10 is arranged around the ionization chamber 5, and a waveguide 11 connected to a microwave power source is connected through a quartz window 12 attached to a part of the ionization chamber 5. Further, a gas introduction pipe 9 having a valve 6 is connected to the ionization chamber 5 .

A case in which a diamond thin film is formed using this apparatus will be specifically described as an example.

First, use a diffusion pump or a turbo pump and an oil rotary pump to evacuate the air from the deaeration port 16 and clean the inside of the vacuum chamber lXl0.
- "Evacuate to below Torr. Set the substrate 3 at about 500°C, then open the valve 6 to introduce gas,
High-purity H3 gas and hydrocarbon gas or organic compound gas are introduced through the gas introduction pipe 9, and the degree of vacuum in the entire vacuum chamber 1 is set to about 10,000 orr. In this state, microwave power of 500 to 100 OW and 1.2
A magnetic field of approximately kG is applied to cause a discharge, and at the same time, an RF' power of 500 to 1000 W is applied to the RF coil 4 to generate RF plasma and grow a film on the substrate 3.

In this example, film formation was performed in this state for about 10 minutes. The thickness of the diamond film formed in this way is approximately 10
It was pm. When the film was measured by Raman spectroscopy, a sharp peak was obtained only at 1330 cm'.

In addition, the Vickers hardness of this film was measured and was approximately 12.
A value of 000 was obtained. This value is the same as that of natural diamond. Furthermore, when the thermal conductivity of the thin film was measured, a value of about 200 W/Kcm was obtained. This is the same as high-pressure synthesized diamond. Thus, it can be seen that a high quality diamond thin film can be obtained at low temperatures according to the present invention.

[Advantageous Effects of the Invention 1] As described above, the present invention combines RF plasma and microwave plasma generated above it to enhance the activation of gas, thereby making it possible to form a high-quality thin film at a relatively low temperature. Note that a high-quality diamond film can be similarly obtained by applying a bias between the extraction electrode provided at the outlet of the microwave ionization chamber and the substrate.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a thin film forming apparatus according to an embodiment of the present invention.

Claims (1)

[Claims] (1) A vacuum chamber in which a substrate holder for holding a substrate is installed, an ionization chamber that generates plasma by the action of microwaves and a magnetic field, and an RF plasma that is generated in the ionization chamber and applied to the substrate in the vacuum chamber. 1. A thin film forming apparatus comprising: an RF coil that activates reaction products in plasma.