JPS61284579A - Plasma concentration type cvd device - Google Patents

Abstract

PURPOSE:To gather high-density plasma to just above a substrate and to deposit uniformly a thin film having high quality on the substrate at a high speed by bending perpendicularly the plasma radiated from the circumference of a vacuum vessel by using a cusp magnetic field thereby concentrating the plasma to the substrate. CONSTITUTION:The plasma of a large area is formed from an annular slit when nitrogen is introduced as the gas to be ionized from plural gas introducing ports 16 of the vacuum vessel 15 toward an annular plasma source 21 in the direction X. The intensity of the magnetic field enough to conduct electric discharge is assured in two intermediate electrodes 18, 19 by making use of the cusp magnetic field generated by two annular magnets 20 in which equiv. currents flow in opposite directions. An anode 23 having a powerful magnet 24 is disposed perpendicularly to the initial plasma flow to concentrate the plasma flow to the neighborhood of the anode 23. For example, a gaseous silane is passed from the ports 26 near the anode 23 by which the nitride film is uniformly deposited on the anode 23.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention applies to semiconductor process technology 2, plasma-intensive CVD (Chemical
The present invention relates to a Vapor Deposition (Vapor Deposition) device.

Conventional technology FIG. 6 is a basic configuration diagram of a conventional plasma CVD apparatus. 1 is a vacuum chamber, 2 is a gas inlet, 3 is an exhaust system, and 4 is a plasma generation device provided in the vacuum chamber 1. high frequency electrode, 6
6 is a sample stand placed opposite the high-frequency electrode 4, and 6 is a sample stand 5.
The sample substrate is placed on top of the sample substrate.

The operation of the conventional plasma CVD apparatus configured as described above will be explained. That is, the sample stage 5 is
For example, silane gas (S i H4) and ammonia gas (NH3) are introduced from the gas inlet 2, and power is applied from the high frequency power source 7 to the high frequency electrode 4, generally at a gas pressure of 1 Q to 105 Pa. Plasma 8 is generated to dissociate SiH4 and NH3, and the dissociated ions and radicals react and combine on the surface of sample substrate 6 to deposit a silicon nitride film.

Yet another conventional example is a plasma transport CVD apparatus, as shown in FIG. 6, in which plasma generated by microwave discharge is transported to a sample to form a film. 9 is a vacuum chamber, 10 is a coil wound around the vacuum chamber 9, 1
1 is a plasma source provided in a vacuum chamber 10, 12 is a sample placed opposite to the plasma source 11, and microwaves are introduced into the plasma source 11 through a waveguide 12. In this conventional example, a film is formed on the sample 6 by transporting plasma 14 generated by microwave discharge to the surface of the sample 13 through thermal diffusion using a parallel magnetic field from the coil 10. It is something.

Problems that F3A is trying to solve However, in the plasma CVD apparatus with the structure shown in Figure 5, the decomposition of S I H4 and NH3 is insufficient, and a large amount of hydrogen is incorporated into the film, resulting in poor bonding. There were problems in that many complete parts remained and a film with good density could not be obtained.

That is, since the sample substrate 6 is located in a place where the plasma 8 is generated, the plasma density is low, and reactions and combinations occur on the surface of the sample substrate 6 without sufficient dissociation.

In addition, in the plasma transport CVD apparatus having the structure shown in Fig. 6, the diameter of the plasma flow 14 is as small as about 2 cm, and the area where a film can be formed is smaller than that of conventional plasma CVD apparatuses, resulting in low productivity. There was a problem.

That is, this is because the diameter of the plasma flow 14 is determined by the diameter of the plasma source 11.

Therefore, the present invention solves the above-mentioned conventional problems.
It is an object of the present invention to provide a plasma-intensive CVD device that can uniformly form a high-quality thin film over a large area at high speed by taking advantage of the features of conventional plasma CVD devices.

Means for Solving the Problems The apparatus of the present invention includes a vacuum chamber, a plasma source installed so that plasma is radiated into the vacuum chamber, an anode disposed perpendicularly to the plasma source, and a plasma source disposed from the plasma source. Some are equipped with a magnetic field to bend the plasma stream to concentrate the emitted plasma onto the anode, and a gas inlet tube to introduce gas near the anode.

For production The effect of this technical means is as follows.

That is, the plasma radiated from around the vacuum chamber is bent in the vertical direction using a cusp magnetic field, and the plasma is concentrated on the substrate.

As a result, high-density plasma can be collected directly above the substrate, and a high-quality thin film can be deposited uniformly at high speed.

EXAMPLE An example of the present invention will be described below with reference to the drawings.

FIG. 1 shows the configuration of a plasma concentrated high speed CVD apparatus in a first embodiment of the present invention.

In FIG. 1, 15 is a vacuum chamber, 16 is a gas inlet, and 1
7 is a discharge cathode, 18 is a first intermediate electrode, 19 is a second intermediate electrode, 2Q is a magnet provided in the first intermediate electrode 18, and 21 is a discharge cathode 17, a first electrode 18, and a second intermediate electrode. electrode 1
9, a ring-shaped plasma source 22 is composed of a coil 23, an anode of the plasma source 21, a rod-shaped magnet 24 placed under the anode 23, and a cooling water 25 for cooling the anode 23; 26 is a ring-shaped gas inlet, and 27 is an exhaust system.

The operation of the plasma concentrated CVD apparatus of the first embodiment configured as described above will be explained below.

First, when a gas to be ionized, such as nitrogen, is introduced into the ring-shaped plasma source 21 in the X direction from a plurality of gas introduction ports 16, a ring-shaped slit (for example, a slit width of 1.5
mm), a large area plasma is generated. Two intermediate electrodes 18, 19 provide a pressure difference between the cathode region and the anode region. By DC power supply 2 days, cathode 17 and 1st
The potential difference between the first intermediate electrode 18 and the second intermediate electrode 19 is, for example, 40 V, and the potential difference between the first intermediate electrode 18 and the second intermediate electrode 19 is, for example, 35 V.
V, the second intermediate electrode 19 and the anode 23 are, for example, 2Q
This is the discharge voltage of V. In order to ensure sufficient magnetic field strength to guide the discharge between the two intermediate electrodes 18 and 19,
A cusp magnetic field created by two ring-shaped magnets 20 in which equivalent currents flow in opposite directions was utilized.

In order to concentrate the plasma emitted horizontally from the plasma source 21 near the anode 23, it is necessary to bend the plasma by nearly 90 degrees. The anode 23 is placed perpendicular to the initial plasma flow and has a strong magnet 24 (for example, a rare earth magnet SmC06) inside it.

The surface of the anode 23 and the S pole surface of the magnet 24 are separated by about 2 crn, so that they can be sufficiently cooled with water. In FIG. 1, the X axis is defined along the initial plasma flow (along the axis of the plasma source 21), and the y
Once the axis is determined, the energy of the electron flow in the plasma is small and the movement is not thermalized in order to change the direction of the plasma. The energy of the electron flow is V. (
eV), it becomes. Equation (1) means that in order to bend the plasma flow, the cyclotron radius of the electrons in the plasma 29 must be smaller than the radius of the plasma flow.

The magnetic field B in the X direction is obtained by a cusp magnetic field created by two coils 22 in which current flows in opposite directions. FIG. 3a shows the magnetic field lines 30 created by the coil 22. FIG. 6 is a schematic diagram showing the direction of current flowing through the coil 22. The central magnetic field in the y direction due to the coil 22 is zero, and the magnetic field B in the y direction is almost independently determined by the magnet 24 of the anode 23.

In order to obtain uniform film deposition at high speed, the relationship between Bx and Ba, the way the plasma flow curves, and the way it is focused on the surface of the anode 23 are influenced.

With the magnetic field configuration shown in FIG. 3, the magnetic field in the plasma diffusion region near the second intermediate electrode 19 can be rapidly reduced. Therefore, it is possible to obtain a wide plasma.

Further, FIG. 6 shows the magnetic field configuration in the second embodiment, and since the magnetic field in the plasma diffusion region near the second intermediate electrode 19 gradually decreases, a focused plasma can be obtained.

In this way, a plasma of nitrogen, for example, concentrated in the vicinity of the anode 23 is obtained. At this time, a nitride film can be deposited on the anode 23 by flowing, for example, silane gas from the ring-shaped gas inlet 26 near the anode 23.

As described above, according to this embodiment, by concentrating the plasma flow directly above the bent anode 23, the plasma density near the anode 23 is increased, and the film deposition rate can be increased in a high vacuum. Further, by optimizing the relationship between the magnetic fields Bx and Ba, it is possible to improve the uniformity of plasma on the surface of the anode 23, and it is possible to improve the uniformity of film deposition even over a large area.

Effects of the Invention The present invention makes it possible to realize a plasma-concentrated CVD apparatus that can uniformly deposit a high-quality thin film at high speed by concentrating high-density plasma directly above a sample.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of a plasma concentrated CVD apparatus according to a first embodiment of the present invention, FIG. 2 is a perspective view thereof, and FIG.
4b and 4a and 4b are schematic diagrams showing magnetic fields, FIG. 5 is a block diagram of a conventional plasma CVD apparatus, and FIG. 6 is a block diagram of a conventional plasma transport CVD apparatus. 16... Vacuum chamber, 21... Plasma source, 23... Anode, 26... Gas inlet, 29... Plasma. Name of agent: Patent attorney Toshio Nakao and one other person
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Claims (2)

[Claims] (1) A vacuum chamber, a plasma source installed so that plasma is radiated into the vacuum chamber, an anode arranged vertically to this plasma source, and a plasma radiated from the plasma source concentrated on the anode. A plasma concentration type CVD apparatus comprising a magnetic field for bending a plasma flow and a gas introduction pipe for introducing gas into the vicinity of the anode. (2) The plasma concentrated CVD according to claim 1, wherein the magnetic field is obtained by a cusp magnetic field arrangement created by two coils sandwiching the plasma source and a magnet placed under the anode. Device.