JPH0650724B2 - Low temperature plasma electromagnetic field control mechanism - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low temperature plasma electromagnetic field control mechanism, and more particularly to a low temperature plasma electromagnetic field control mechanism for controlling low temperature plasma generated for thin film surface treatment with an electromagnetic field.

[Background of the Invention]

In recent surface treatment equipment such as semiconductor thin film generation and etching, low temperature plasma such as ionized or excited polyatomic molecules and compounds is used to improve film uniformity, film formation rate and surface treatment rate. Things are widely adopted.

6 to 8 show different semiconductor thin film manufacturing apparatuses using conventional low temperature plasma.

FIG. 6 shows a parallel plate electrode type thin film manufacturing apparatus. The vacuum container 1 is configured to have an exhaust hole 5 and a supply hole 6, and inside thereof, a pair of parallel plate electrodes 2 and 3 to which a high frequency alternating current is applied are arranged. The electrode 3 also serves as a sample table, and the substrate 4 is mounted thereon.

After evacuating the inside of the vacuum container 1 through the exhaust hole 5, the electrodes 2,
A material gas is injected from the supply hole 6 and ionized while applying a high-frequency electric field between the electrodes 3, and a low temperature plasma is used to grow a thin film on the substrate 4.

FIG. 7 shows a thin-film manufacturing apparatus using the induction coil 7. The induction coil 7 is arranged on the outer periphery of the vacuum container 1 so as to surround the electrode 3, and the induction electric field generated by the induction coil 7 is used.

In the case of both of these thin film manufacturing apparatuses, the low temperature plasma of the ionized material gas reaches the sample substrate 4 by free diffusion. Therefore, the reaction probability on the surface of the substrate 4 varies depending on the location, and the film thickness after film formation tends to be non-uniform. The rate of film thickness generation cannot be easily controlled because ionization energy must be kept constant.

FIG. 8 shows a conventional plasma electromagnetic field control mechanism according to another embodiment.

In the thin film manufacturing apparatus according to this example, the plasma generation chamber 12 and the reaction chamber 13 are separated from each other, and the magnetic field coil 8 is arranged outside the plasma generation chamber 12. The magnetic field generated by the magnetic field coil 8 and the 2.45 GHz microwave 10 injected from the waveguide 9 cause electron cyclotron resonance to ionize the material gas injected from the supply hole 6, and the low temperature plasma from the extraction port 14. The material gas in the state of the reaction chamber 1
3, the thin film is grown on the sample substrate 4. This device is the first in "Applied Physics" Vol. 52, No. 2 (1983).
You are invited to page 18.

In this manufacturing apparatus, a low-temperature plasma 11 is generated by applying a magnetic field that vertically penetrates the sample substrate 4 by a magnetic field coil 8.
It gives direction to the kinetic energy of. However, the film uniformity and the generation rate were not sufficient because free diffusion still occurred in the magnetic field direction.

[Object of the Invention]

An object of the present invention is to provide a low temperature plasma electromagnetic field control mechanism capable of controlling the energy and directionality of low temperature plasma.

[Outline of Invention]

The present invention is to controllably provide means for applying a magnetic field to guide a low temperature plasma and controllably provide means for applying an electric field in a direction orthogonal to the magnetic field. Therefore, the energy and direction of the low temperature plasma are controlled.

Example of Invention

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

The low-temperature plasma electromagnetic field control mechanism of FIG. 1 is similar to the apparatus of FIG. 8 in the structure in the vicinity of the plasma generation chamber 12, but is different in the vicinity of the reaction chamber 13 and the electromagnetic field configuration.

A magnetic field coil 15 is arranged on the outer periphery of the reaction chamber 13, and the magnetic field generated by the magnetic field coil 15 is continuously connected to the magnetic field generated by the magnetic field coil 8 of the plasma generation chamber 12. A rod-shaped electrode 16 is provided at the center of the reaction chamber 13.
Are arranged, and the rod-shaped electrode 16 and the reaction chamber container 18 are arranged.
A power supply 17 for applying an arbitrary voltage is connected between them. A sample substrate 4 is fixed to a sample table 3 arranged substantially parallel to and vertically to the rod-shaped electrode 16.

Considering the cylindrical coordinate (r, Θ, z) system shown in the figure, the low temperature plasma generated in the plasma generation chamber 12 in the same manner as the conventional example shown in FIG. Plasma generation chamber 1 with a gradient ▽ B in the magnetic field B _Z
By being continuously connected to the magnetic field of 2, the translational energy ε ₁ in the magnetic field line direction is obtained. At the same time, by applying an arbitrary voltage to the rod-shaped electrode 16 in the reaction chamber 13, an electric field E _r in the radial direction, that is, the r direction is generated.
_{Due to r} and the axial magnetic field B _Z , a force F _Θ = E _r × B _Z (vector product) in the circumferential direction is applied to the low temperature plasma in the reaction chamber container, and kinetic energy ε _{2 in the} direction orthogonal to the magnetic force lines is obtained.
Therefore, near the surface of the sample substrate 4, the angle of incidence of the low temperature plasma on the surface of the sample substrate 4 and the kinetic energy of the charged particles can be controlled.

FIG. 2 shows the electromagnetic field configuration of the reaction chamber 13 of the above mechanism, where the magnetic field B _{Z in the} axial direction, that is, the z direction, and the radial electric field E _r.
As a result, the low temperature plasma is Lorentz F _Θ (= E _r × B
_It moves in the circumferential direction, that is, in the θ direction by the force of _{Z 2} ).

The magnetic field coil 8 generates a fixed magnetic field necessary for generating low-temperature plasma, whereas the magnetic field coil 15 is connected to a power source capable of controlling the strength of the magnetic field, and the power source 17 also controls the strength of the electric field. The kinetic energy in the direction of magnetic force or the axial direction (z direction) along the magnetic field B _Z of the low-temperature plasma and the kinetic energy in the direction perpendicular to the axis (r, Θ direction) due to the electric field _Er and the magnetic field B _Z orthogonal thereto. It is possible to control the directionality. This is because by controlling the kinetic energy of charged particles and reactive neutral atoms and molecules on the sample substrate 4, and at the same time controlling the input power and the electromagnetic field configuration that determines the loss process, the density of low temperature plasma, It is possible to control the degree of ionization and the like. That is, it is possible to control microscopic quantities (kinetic energy, velocity components, etc.) of the low-temperature plasma on the sample substrate and macroscopic quantities (distribution of density, temperature, ionization degree, etc.).

FIG. 3 is a vertical sectional view showing the control of a low temperature plasma electromagnetic field according to another embodiment, and FIG. 4 is a sectional view taken along line IV-IV in FIG.

The plasma generation chamber 12 and the magnetic field coil 15 in this embodiment are the same as those in the previous embodiment, but the internal structure of the reaction chamber 13 is different from that in the previous embodiment.

Inside the reaction chamber 13, three pairs of electrodes 24, 25 and 26, which also function as sample holders for generating an electric field E _{1 in the} direction perpendicular to the axis (r, Θ direction) in the cylindrical coordinates (r, Θ, z), face each other. It is arranged. A three-phase AC power supply 23 is connected to the three pairs of electrodes and rotates the electric field E ₁ in the circumferential direction, that is, in the Θ direction. A sample substrate 4 is attached to each electrode in the z direction near the reaction chamber wall 18 of the reaction chamber 13.

Therefore, Lorentz F ₁ (= E ₁ ×) due to the magnetic field B _{Z in the} z direction by the magnetic field coil 15 and the electric field E ₁ is applied to the low temperature plasma.
B _Z (vector product) is added, and rotation is performed at the frequency of the three-phase AC power supply 23 for electric field generation. In the vicinity of the sample substrate 4 attached to the electrodes 24 to 26 also serving as the sample table, the low temperature plasma and the reactive neutral atoms and molecules are directional while energy is relaxed by the drift due to the Lorentz force and the rotation of the electric field. The particle bundle having the property reaches the working substrate 4.

Also in this embodiment, the magnetic field coil 15 capable of controlling the magnetic field in the z direction and the electrode 2 capable of controlling the electric field in the r and Θ directions.
By using 4, 25, 26 and the power source 23, the same effect as that of the previous embodiment can be achieved, and a directional particle bundle can be obtained. This is a three-phase AC power supply 23
Not limited to this, polyphase alternating current can be used. Power supply 23
Is a direct current power source, and electrodes 24, 25, 2 are set at regular intervals.
It is also possible to change the connection with 6.

FIG. 5 shows a low temperature plasma electromagnetic field control mechanism according to still another embodiment of the present invention. The same reference numerals as those used in the previous embodiment denote the same items.

In this example, electrodes 27 and 28 are arranged in a vacuum plasma generation chamber / reaction chamber 13, and a power source 29 is placed between the electrodes 27 and 28.
A high frequency electric field is applied to ionize the material gas. The generated low temperature plasma obtains translational energy by the axial magnetic field generated by the magnetic field coil 15. Further, the power source 1 is connected to the rod-shaped electrode 16 arranged between the electrodes 27 and 28.
A predetermined voltage is applied from 7 to generate an electric field at right angles to the magnetic field by the magnetic field coil 15, and the electric field and the magnetic field apply a circumferential force to the low temperature plasma in the reaction chamber 13 to move in a direction orthogonal to the magnetic field lines. Getting energy. By fixing the sample substrate 4 to the electrode 28, it is possible to obtain the same effect as that of the previous embodiment.

If the low-temperature plasma control mechanism according to each of these embodiments is used for thin film formation, for example, it is possible to improve the performances such as thin film uniformization, flattening, and film formation rate during generation.

〔The invention's effect〕

As described above, according to the present invention, the means for generating a controllable magnetic field in the axial direction such as the magnetic field coil 15 and the power sources 17, 23 and the electrode 1 for generating a controllable electric field orthogonal to this magnetic field.
Since the means such as 6, 24, 25, and 26 are provided, the energy and directionality of particles reaching the sample substrate can be controlled.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of a low temperature plasma electromagnetic field control mechanism according to an embodiment of the present invention, FIG. 2 is an electromagnetic field configuration diagram of FIG. 1, and FIG. 3 is a low temperature plasma according to another embodiment of the present invention. FIG. 4 is a vertical sectional view of the electromagnetic field control mechanism, FIG. 4 is a sectional view taken along line IV-IV of FIG. 3, and FIG. 5 is a vertical sectional view of a low temperature plasma electromagnetic field control mechanism according to a further different embodiment of the present invention. FIG. 6, FIG. 7 and FIG. 8 are vertical sectional views of thin film manufacturing apparatuses according to different conventional embodiments. 8 ... Magnetic field coil, 12 ... Plasma generation chamber, 13 ...
Reaction chamber, 15 ... Magnetic field coil, 16 ... Rod electrode, 17
...... Power supply, 23 …… Three-phase AC power supply, 24-28 …… Electrodes.

Claims (5)

[Claims] 1. A low-temperature plasma electromagnetic field control mechanism for generating and reacting low-temperature plasma in a vacuum chamber, means for giving a controllable magnetic field to the low-temperature plasma in a predetermined direction, and And a means for applying a controllable electric field so that the electric field is controllable in a substantially rectangular direction. 2. A low temperature plasma electromagnetic field control mechanism according to claim 1, wherein a magnetic field coil is used as the means for applying the magnetic field. 3. The device according to claim 1, wherein the means for applying the electric field is a rod-shaped electrode provided substantially in the width direction of the magnetic field, and a predetermined voltage is applied to the rod-shaped electrode. A low-temperature plasma electromagnetic field control mechanism characterized by comprising a power supply for applying. 4. The device according to claim 1, wherein the means for applying the electric field includes a plurality of pairs of electrodes which are arranged to face each other so as to be orthogonal to the magnetic field, and a pair of the electrodes. A low temperature plasma electromagnetic field control mechanism comprising: a power source for sequentially applying a predetermined voltage in the circumferential direction of the. 5. A low-temperature plasma electromagnetic field control mechanism according to claim 4, wherein a polyphase alternating current is used as the power source.