JPS6377119A - Plasma processor - Google Patents

Abstract

PURPOSE:To make a plasma process uniform thereby to increase the processing range of a plasma processor by bringing a center shaft in coincidence with the periphery of a plasma generator, axially disposing a plurality of solenoid coils, energizing any of the coils and altering the combination of the coils to be energized. CONSTITUTION:A plasma generator 1 has solenoid coils 7, 14, 15 for axially generating a static magnetic field, a high-frequency waveguide 4 for introducing a high-frequency magnetic field perpendicularly to the axial direction and a plasma generating glass tube 11. A high-frequency power to the waveguide 4 is supplied by a magnetron 5, and when gas is supplied from a tube 9, a plasma stream 13 is generated along a dispersed magnetic field formed in a reactor 8. When the combination of the coils 7, 14, 15 to be energized is altered and the plasma stream is controlled, the film thickness distribution on a substrate 3 can be altered to form a uniform film thickness distribution in a wide range.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a plasma processing apparatus which is a semiconductor processing apparatus, and in particular to a plasma processing apparatus which generates plasma using electron cyclotron resonance and which enables uniform plasma processing over a wide area. This relates to processing equipment.

[Conventional technology]

FIG. 6 is a cross-sectional configuration diagram showing a conventional plasma processing apparatus disclosed in, for example, Japanese Unexamined Patent Publication No. 57-79621.
In the figure, (1) is the plasma generation section, (2) is the stage, (3) is the substrate, (4) is the waveguide, and (5) is the magnetron.

(6) is for magnetron [i, (7) is solenoid coil.

(8) is the plasma reaction section, (9) is the gas supply pipe, 0 is the exhaust pipe, αυ is the glass tube for plasma generation, and (2) is the DC power supply.

α■ is the plasma flow.

Next, the operation will be explained. FIG. 5 shows a basic embodiment of a conventional apparatus, which is composed of a plasma generating section (1) and a plasma reaction section (8).

The plasma generation section (1) includes a solenoid coil (7) that generates a static magnetic field that is nonuniform in the axial direction, a high-frequency waveguide (4) that introduces a high-frequency electric field perpendicular to the axial direction, and a glass tube for plasma generation. α and has a high frequency waveguide (4)
A magnetron (5) supplies high frequency power to the plasma generating glass tube (Ql), and gas is supplied to the plasma generating glass tube (Ql) through a gas supply tube (9).

Plasma is formed by electron cyclotron resonance, which will be explained below. Now, the strength of the non-uniform static magnetic field in the axial direction (Z direction) is B
(z). The high frequency waves supplied into the high frequency waveguide (4) by the magnetron (5) generate a non-uniform high frequency electric field Erf within the plasma generating part (1), which is shaped to resonate according to the frequency of the high frequency wave. (z) is formed. High frequency electric field Erf(z) within the plasma generation part (1)
FIG. 6 shows the static magnetic field strength Bz (z) in the Z direction that causes electron cyclotron resonance. The line from point (C) to point ■ is B
z (z) connects points of magnetic field strength that cause resonance with the high-frequency electric field Erf (z).

Electrons perform the well-known cyclotron motion in the static magnetic field B, and the cyclotron angular frequency is expressed by Wc=eB/m. (However, m is the mass of the electron.) If the angular frequency of the high-frequency electric field Erf (z) in the plasma generation part (1) is W, and the cyclotron resonance condition of W = Wc is established, then
High-frequency energy is continuously supplied to the electrons, increasing the energy of the electrons.

Under such cyclotron resonance conditions, the gas supply pipe (
9) When gas at an appropriate gas pressure is introduced into the chamber, the electrons generated in the pre-discharge state are continuously supplied with energy from the high frequency and become in a high energy state. Through the collision process, plasma is generated, and this generated Radio frequency power is further injected into the plasma under resonance conditions.

Therefore, for example, the gas introduced into the gas supply pipe (9) is
In the case of iH4, by appropriately adjusting the high frequency power in addition to the gas pressure, Sl, SiH, SiH2,
SiH.

At the same time, it is possible to control ions such as Si', and the type, concentration, or energy of each ion.
The type, concentration, or energy of radicals such as "SiH" can be controlled.

On the other hand, the non-uniform static magnetic field B (z) and the non-uniform electric field Er
Between f(z), an axial force Fz given by the following equation acts on the electron, and the electron is accelerated in the axial direction.

B, where μ is the magnetic moment, Wo is the energy of circular motion of electrons, and Bo is the magnetic flux density at the plasma generation area.

M is the mass of the ion.

Therefore, the electrons in the plasma generated in the plasma generation part (1) in FIG. (z) causes the plasma as a whole to be accelerated in the axial direction, and a plasma flow along the axial direction is generated in the plasma reaction section (8).

Since the magnetic field lines created by the solenoid coil (7) have an r-direction component in the plasma reaction section (8) (that is, become a divergent magnetic field), the plasma flow α spreads along the magnetic field lines. .

The plasma processing apparatus according to the embodiment of FIG. 5 can be applied to various dish surface treatments including plasma etching, plasma CVD, and plasma oxidation, and can effectively perform these treatments.

[Problem that the invention seeks to solve]

Since the conventional plasma processing apparatus using electron cyclotron resonance is configured as described above, the Z-direction component Bz (z) of the static magnetic field that resonates with the high-frequency electric field has a specific value as shown in Figure Hayabusa 6. Furthermore, in order to perform plasma processing on large-diameter substrates, it is necessary to increase the inner diameter of the solenoid coil, which increases the size of the equipment. Ta.

This invention was made to solve the above-mentioned problems, and aims to provide a plasma processing apparatus that can improve the uniformity of plasma processing and can also handle large-diameter substrates.

[Means for solving problems]

The plasma processing apparatus according to the present invention arranges a plurality of solenoid coils aligned in the axial direction around a plasma generation part with their central axes coincident, and applies current to any one of the solenoid coils. Along with flowing,
The combination of solenoid coils that weaken the current is changed.

[Effect]

The plasma processing apparatus according to the present invention controls the current flowing through each of a plurality of solenoid coils arranged in the axial direction,
By changing the combination of solenoid coils through which current flows, the divergent magnetic field distribution created by the solenoid coils in the plasma generation section and the plasma reaction section can be changed, and the plasma flow drawn from the plasma generation section to the plasma reaction section can be controlled. It becomes possible. This makes it possible to perform uniform plasma processing on large-diameter substrates with a small device.

〔Example〕

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

FIG. 1 is a cross-sectional configuration diagram showing a plasma processing apparatus according to an embodiment of the present invention, and in the figure, (7).

αJ and QFJ are a plurality of solenoid coils disposed around the plasma generating part ( ), and are arranged in the axial direction with their respective central axes coincident. α →, αη, (to) turn ON and OFF the current flowing through each solenoid coil (7), αX, and αQ.
The FF switch (2), α, and the solenoid coil (7).

This is a DC power supply that supplies current to α→, 06.

Next, the operation will be explained.

The plasma generation section (1) includes a plurality of solenoid coils (7), α→, αυ and 1ll that generate a static magnetic field in the axial direction.
It has a high-frequency waveguide (4) that introduces a high-frequency electric field perpendicular to the l11 direction and a glass tube for plasma generation (01), and a magnetron (5) that supplies high-frequency power to the high-frequency waveguide (4). ), the plasma generation glass tube a
Gas is supplied to υ through a gas supply pipe (9).

Plasma formation is carried out by electron cyclotron resonance, which is generated by a high-frequency electric field Erf(z
), solenoid coil (7), Q41. It is generated by a composite static magnetic field Bz(z) of αθ.

In addition, the axial force Fz acting on the electrons causes one child in the plasma generated in the z part (1) to be accelerated in the axial direction toward the plasma reaction part (8), and for this reason, ions are generated in the plasma. An electric field Eo(z) is created in the axial direction that accelerates the . The plasma as a whole is accelerated in the axial direction by this electric field Eo (z), and the plasma reaction part (
8) A diverging magnetic field (plasma flow α along this line) is generated.Now, in Fig. 1, for example, switch αe is turned to O.
When N, switch αη, (to) is turned OFF and a current is applied only to the solenoid coil (7), the plasma flow (18a) and the film thickness distribution of the thin film formed on the substrate (3) at that time are as follows. The result will be as shown in FIG. 8(a) and FIG. 8(a). Also, for example, by turning off the switch Qe and turning on the switches αη and 0, the solenoid coil 04. (If a current is applied only to 5f; j, the plasma flow (18b) and the film thickness distribution of the thin film formed on the substrate will be as shown in Fig. 2 (b) and Fig. 8 (6). Therefore, , for example, the current flowing through the eight solenoid coils (7), Q4), and Qυ is passed through the switches αQ and α.

When the current waveforms (a), (b), (C) (/f Jl/span width t=several μs to several S) shown in Fig. 4 are applied to each of them using α-uniform ON/OFF control, the plasma flow α
→ The conditions shown in FIGS. 2(a) and 2(b) are repeated alternately, so that a thin film with a uniform thickness distribution is formed on the substrate.

As mentioned above, the solenoid coil (7) that conducts current.

(14. By changing the combination of αO and controlling the plasma flow, the film thickness distribution on the substrate (3) can be changed, so for example, an amorphous silicon film with a uniform film thickness distribution over a wide range can be formed. It becomes possible.

The plasma processing apparatus according to the embodiment shown in FIG. 1 can be applied to various surface treatments including plasma etching, etching, plasma CVD, and plasma oxidation, and can perform uniform treatments over a wide range.

In the above embodiment, the number of solenoid coils was eight, but it may be any number, and even if the current flow time is varied other than the inverted position shown in Fig. 4, the same effect as in the above embodiment can be achieved. It has the effect of

〔Effect of the invention〕

As described above, according to the present invention, a plurality of solenoid coils are arranged in the axial direction around the plasma generation part with their respective central axes coincident, and any one of the plurality of solenoid coils is Since the combination of the solenoid coils through which the current flows is changed as well as the current flow, the plasma flow from the plasma generation section to the plasma reaction section can be controlled, making it possible to perform uniform plasma processing. Furthermore, it is possible to perform plasma processing with high accuracy even on large diameter substrates.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional configuration diagram showing a plasma processing apparatus according to an embodiment of the present invention, and FIG. 2(a) and FIG. A cross-sectional view and a distribution diagram showing the plasma flow when current is applied to the substrate and the film thickness distribution of the thin film formed on the substrate, Figure 2 (
b) and FIG. 8(b) respectively show the plasma flow and the film thickness distribution of the thin film formed on the substrate when current is passed through the lower two of the solenoid coils according to an embodiment of the present invention. A sectional view and a distribution diagram, FIGS. 4(a), 4(b), and 4(c) are waveform diagrams each showing the current flowing to a solenoid coil according to an embodiment of the present invention, and FIG. 5 shows a conventional plasma processing apparatus. The cross-sectional configuration diagram and FIG. 6 are distribution diagrams showing the distribution of the static magnetic field strength Bz(z) in the Z-axis direction, which causes electron cyclotron resonance, in the plasma generation part in a conventional plasma processing apparatus. (1)...Plasma generation part (3)...Substrate (7)θ→αQ...Solenoid coil (8)...
・Plasma reaction section Q3 (113a) (18b)...
Plasma flow 000 force (c)...switch (2) (
1'l) --- DC source Note that in the figures, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] Generate plasma using electron cyclotron resonance,
In a device that performs plasma processing on a substrate, a plurality of solenoid coils arranged in the axial direction with their respective central axes coincident are arranged around the plasma generation part that generates the plasma, and any one of the plurality of solenoid coils is arranged. A plasma processing apparatus characterized in that a current is passed through the solenoid coils and a combination of the solenoid coils through which the current is passed is changed.