JPH01304724A - Plasma processing apparatus - Google Patents

Abstract

PURPOSE:To achieve uniform and high speed plasma processing by arranging second plural solenoid coils around a plasma reactor so that the axes of the coils do not meet each other and applying different phase currents to the solenoid coils successively. CONSTITUTION:A plurality of second solenoid coils 14a-14d are placed around a plasma reactor 8 such that each center axis does not meet each other. As magnetic field generated by those coils 14a-14d revolves, a plasma current 13 also revolves around Z axis in accordance with the revolving magnetic field. Therefore, the plasma current 13 can be drawn in a wide area in the plasma reactor 8. Also, a first solenoid coil 7 and the second solenoid coils 14a-14d form a weak mirror magnetic field, thereby the plasma current diverging in the plasma reactor 8 is focused, and loss of the plasma at the side wall, etc., of the plasma reactor is reduced. Furthermore, higher density plasma is obtained by plasma confinement. Thus, the plasma processing can be applied uniformly in a wide area and at high speed in the plasma reactor 8.

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 that uses electron cyclotron resonance to generate plasma over a wide area uniformly and at high speed. 0 [Prior Art] Fig. 4 is a cross-sectional configuration diagram showing a conventional plasma processing apparatus described in, for example, Japanese Unexamined Patent Publication No. 57-79621. , 1 is a plasma generation part, 2 is a stage, 3
1 is a substrate, 4 is a waveguide, 5 is a magnetron, 6 is a driving power source, 7 is a solenoid coil, 8 is a plasma reaction section, 9 is a gas supply pipe, 10 is an exhaust pipe, 11 is a glass tube for plasma generation, 12 is a A DC power supply, 13 is a plasma flow.

Next, the operation will be explained.

The plasma generation section 1'' includes a solenoid coil T that generates a static magnetic field that is non-uniform 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 11 for plasma generation. High frequency power is supplied to the high frequency waveguide 4 by a magnetron 5, and gas is supplied to the plasma generating glass tube 11 through a gas supply pipe 9.

Plasma is formed by electron cyclotron resonance, which will be explained next.

Now, let B(z) be the strength of the nonuniform static magnetic field in the axial direction (two directions). The high-frequency waves supplied into the high-frequency waveguide 4 by the magnetron 5 form a non-uniform high-frequency electric field Erf(z) in the plasma generation section 1, which is shaped to resonate according to the frequency of the high-frequency waves. .

Electrons perform the well-known cyclotron motion in the static magnetic field B, and the cyclotron angular frequency ωC is expressed as ωC=eB/m. (However, m is the mass of the electron.) If the angular frequency of the high-frequency electric field Er f (z) in the plasma generation section 1 is ω, and the cyclotron resonance condition of ω = ωC is satisfied, the high-frequency energy is transferred to the electrons. Continuous supply increases the energy of electrons.

Under such cyclotron resonance conditions, the gas supply pipe s
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 plasma Furthermore, high frequency power is injected under resonance conditions.

Therefore, for example, the gas introduced into the gas supply pipe 9 is
(If it is 4, by appropriately adjusting the high frequency power in addition to the gas pressure, 81, SIH.

It is possible to control the type, concentration, or energy of radicals such as 's, 5IHX, etc. during the run, which can control ions such as Is and 5tI(s), and the type, concentration, or energy of each ion.

On the other hand, the non-uniform static magnetic field B(z) and the non-uniform electric field Erf(
z), an axial force Fz given by the following equation acts on the electrons, and the electrons are accelerated in the axial direction.

B where μ is the magnetic moment, ω0 is the energy of circular motion of electrons, Bo is the magnetic flux density at the plasma generation part, and M is the mass of the ions.

Therefore, electrons in the plasma generated in the plasma generation section 1 in FIG. 4 are accelerated in the axial direction toward the plasma reaction section 8,
For this reason, there is an electrostatic field Eo in the plasma that accelerates ions.
(z) is formed in the axial direction.

The plasma as a whole is accelerated in the axial direction by this electrostatic field E o (z), and a plasma flow 13 along the axial direction is generated in the plasma reaction section 8 . The magnetic field lines created by the solenoid coil 7 are connected to the plasma reaction section 8.
Then, since it has an r-direction component, the plasma flow 13
spreads along the magnetic field lines.

Such plasma processing equipment is capable of plasma etching,
It can be applied to various surface treatments such as plasma CVD and plasma oxidation, and these treatments can be performed effectively.

[Problem to be solved by the invention]

Since the conventional plasma processing apparatus using electron cyclotron resonance is configured as described above, the axial component of the magnetic flux density near the substrate is non-uniform in the radial direction as shown in Figure 5(a). be. Since the plasma flow spreads along the lines of magnetic force, it becomes non-uniform in the radial direction.For example, when forming a thin film by plasma CVD, the film thickness distribution becomes non-uniform as shown in Figure 5 (b). It is difficult to obtain uniformity. Furthermore, since the lines of magnetic force diverged, there was a large loss of plasma at the side walls of the reaction section, etc., resulting in poor plasma processing efficiency.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a plasma processing apparatus that can uniformly and rapidly perform plasma processing on a large-diameter substrate.

[Means to solve the problem]

In the plasma processing apparatus according to the present invention, a first solenoid coil is arranged around a plasma generation section, and a plurality of second solenoid coils whose central axes do not coincide with each other are arranged around a plasma reaction section. Currents with different phases are sequentially passed through the second solenoid coil.

[Effect]

In the plasma processing apparatus according to the present invention, a magnetic field in which the axial magnetic field moves can be formed by sequentially flowing currents with different phases through the plurality of second solenoid coils, and the plasma flow can undergo linear motion or rotational motion together with the moving magnetic field. plasma can be drawn out over a wide area. In addition, plasma is confined by a mirror magnetic field formed by a first solenoid coil and a plurality of second solenoid coils arranged around the plasma generating section, and a high-density plasma is obtained. Therefore, in the plasma reaction section, plasma processing can be performed uniformly over a wide area and at high speed.

〔Example〕

Hereinafter, one embodiment of the present invention will be described 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 the same parts as in the previous figures are given the same reference numerals. In the same figure, 14a, 14b, 14
c, 14d (generally referred to as 14) are plasma reaction parts 8
A plurality of second solenoid coils are arranged around the second solenoid coil so that their central axes do not coincide with each other. Reference numeral 15 denotes a power source that sequentially causes currents with different phases to flow through the plurality of second inlenoid coils 14.

Next, the operation will be explained.

As in the past, the plasma generated in the plasma generation section 1 is
Although it is drawn out to the plasma reaction section 8, the plasma reaction section 8
In this case, the plasma flow 13 is caused by the second solenoid coil 14a,
Under the influence of the magnetic field formed by 14b, 14C, and 14d, the center of the plasma flow 13 deviates from the central axis of the first solenoid coil T, as shown in FIG. Second solenoid coil 14a.

Since the magnetic field formed by 14b, 14c, and 14d rotates, the plasma flow 13 also rotates as the magnetic field rotates.
Rotate around the axis. Therefore, the plasma flow 13 is drawn out over a wide range in the plasma reaction section 8. In addition, since a weak Measy-shaped magnetic field is formed by the first solenoid coil 7 and the second solenoid coils 14a, 14b, 14c, and 14d, the plasma flow that is about to diverge in the plasma reaction section 8 is constricted, and the plasma reaction section side wall Plasma loss is reduced. Furthermore, high-density plasma can be obtained by confining the plasma.

Therefore, in the plasma reaction section 8, plasma processing can be performed uniformly and at high speed over a wide area. For example, if the gas introduced into the gas supply pipe 9 is 5ia4, Sr, StH, and 5iHs are generated by electron cyclotron resonance.

- Ions such as +5IH8 and radicals such as 81,5IHX are generated in the plasma generation section 1 and drawn out to the plasma reaction section 8. When , the rotating magnetic field causes plasma flow 1
3 rotates and the plasma is confined, so that an amorphous silicon film with a uniform thickness distribution is formed on the large-diameter substrate 3 at high speed in the plasma reaction section 8.

The plasma processing apparatus according to the embodiment shown in FIG. 1 can be applied to various rice and wheat surface treatments such as plasma etching, plasma CVD, and plasma oxidation, and can perform uniform treatment over a wide range at high speed.

In the above embodiment, four second solenoid coils +14a, 14b, and 14c are used to generate the rotating magnetic field.

14d shows an example in which the current i shown in FIG. 3 is passed,
The number of second renoid coils may be more than one (however, if there are two, the axial magnetic field will move linearly, and if there are three or more, it will move rotationally). The current waveform is also shown in Figure 3. In addition to the trapezoidal current waveform, a similar effect can be obtained by sequentially flowing an AC half wave, triangular wave, or pulse wave current waveform through the plurality of second solenoid coils.

〔Effect of the invention〕

As described above, according to the present invention, a first solenoid coil is disposed around a plasma generating section, and a plurality of second solenoid coils whose central axes do not coincide with each other are arranged around a plasma reaction section.
By arranging solenoid coils and sequentially passing currents with different phases through a plurality of second solenoid coils, it is possible to cause the plasma flow to move linearly or rotationally, and to confine the plasma. It also has the effect of allowing uniform plasma processing to be performed at high speed.

[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, FIG. 2 is a plan configuration diagram showing the arrangement of a second solenoid coil according to an embodiment of the present invention, and FIG. 3 is a diagram showing the arrangement of a second solenoid coil according to an embodiment of the present invention. A waveform diagram showing the current flowing through the second solenoid coil according to one embodiment, FIG. 4 is a cross-sectional configuration diagram showing a conventional plasma processing device, and FIG. 5 is a magnetic flux density distribution diagram and film thickness in the conventional plasma processing device. It is a distribution map. 1...Plasma generation section, 2...Stage, 3...
・Φ Substrate, 4... Waveguide, 5... Magnetron, 6... Drive power supply, 7... First solenoid coil, 8... Plasma reaction section, 9... ... Gas supply pipe, 10 ... Exhaust pipe, 11 ... Glass tube for plasma generation, 12 ... DC power supply, 13 ... Plasma flow, 14a, 14b, 14c, 14a @ 1161
1 2nd solenoid coil, 15...power supply.

Claims (1)

[Claims] In a plasma processing apparatus that generates plasma using cyclotron resonance and plasma-processes a substrate, a first solenoid coil is disposed around a plasma generation section that generates the plasma, and a first solenoid coil is arranged around a plasma reaction section where the plasma reacts. A plasma processing apparatus characterized in that a plurality of second solenoid coils are arranged whose central axes do not coincide with each other, and currents having different phases are sequentially passed through the plurality of second solenoid coils.