WO2009048294A2

WO2009048294A2 - Magnetized inductively coupled plasma processing apparatus and generating method

Info

Publication number: WO2009048294A2
Application number: PCT/KR2008/005972
Authority: WO
Inventors: Ki Woong Hwang
Original assignee: Seoul National University Industry Foundation
Priority date: 2007-10-11
Filing date: 2008-10-10
Publication date: 2009-04-16
Also published as: WO2009048294A3

Abstract

Disclosed herein is a magnetized, inductively coupled plasma processing apparatus and plasma generation method. The inductively coupled plasma processing apparatus according to an embodiment of the present invention includes a vacuum chamber (200). A sample seating means (205) is provided in the vacuum chamber. An antenna (210) is configured to generate plasma in the vacuum chamber. At least one pair of permanent magnets (230, 235) are arranged above the antenna and below the sample seating means (205) and are configured to generate a magnetic field in a vertical direction of the vacuum chamber and to have opposite polarities on the facing ends.

Description

[DESCRIPTION]

[invention Title]

MAGNETIZED INDUCTIVELY COUPLED PLASMA PROCESSING APPARATUS AND GENERATING METHOD

[Technical Field]

The present invention relates, in general, to an inductively coupled plasma processing apparatus and plasma generation method, and, more particularly, to a plasma processing apparatus and plasma generation method that enable a magnetic field to be generated in a plasma generation space using permanent magnets so as to facilitate the generation of high-density plasma at low pressure and improve the uniformity of plasma distribution over a sample, thus enabling plasma to be uniformly processed over the entire area of the sample.

[Background Art]

Generally, as plasma generation apparatuses, a capacitively coupled plasma source, an inductively coupled plasma source, a plasma source using helicon wave, a microwave plasma source, etc. have been proposed. Of the apparatuses, the inductively coupled plasma source capable of easily forming high-density plasma has been widely used.

FIG. 1 is a diagram showing an inductively coupled plasma generation apparatus that is generally used in the prior art. The above-described inductively coupled plasma generation apparatus 1 includes a chamber 101 for generating plasma 106, a gas injection port 102 for supplying a reaction gas into the chamber 101, and a vacuum pump 103 for forming a vacuum in the chamber 101 and discharging the reaction gas after the reaction is terminated. Furthermore, in the chamber 101, a substrate holder 105 for allowing a processing target substrate 104

(for example, a wafer) to be seated thereon is installed.

An antenna 107 connected to a Radio Frequency (RF) power source 109 is installed on the top of the chamber 101.

When power is supplied from the RF power source 109, which is impedance-matched with the antenna 107 through an impedance-matching unit 108, RF power, that is, RF voltage and RF current, are supplied to the antenna 107. The RF current flowing through the antenna 107 forms a magnetic field along the vertical direction of a dielectric substance 110 for isolating the antenna 107 in the inner space 111 of the reaction chamber 101. Due to this magnetic field, an induced electric field is formed. In this case, reaction gas in the chamber 101 obtains energy sufficient for ionization from the inductively formed electric field, and forms the plasma 106. The formed plasma 106 flows into the substrate 104 seated on the substrate holder 105 through another RF power source 112 is connected for supplying a negative DC bias voltage, thus processing the substrate 104.

Meanwhile, the density of the plasma 106 formed in the chamber 101 is further increased by the induced electric field attributable to the magnetic field, rather than by the electric field formed in the chamber 101. Such plasma is called inductively coupled plasma and a piece of equipment for generating this is called an inductively coupled plasma generation apparatus or an inductively coupled plasma source. This plasma generation apparatus is advantageous in that high-density plasma can be formed at high operation gas pressure, but is disadvantageous in that, when gas pressure becomes lower, it is difficult to ignite and maintain plasma.

FIG. 2 is a diagram showing a planar spiral antenna widely used in the above-described plasma generation apparatus. The planar spiral antenna is constructed such that more electromagnetic waves are formed in a center portion thereof. Accordingly, the distribution of densities of generated inductively coupled plasma is not uniform over a space, and has a shape in which density is high in the center portion of a reactor and is decreased toward the edge of the reactor. Therefore, in order to actually process a large-area substrate having a size of more than 300 mm, the formation of plasma, having uniform distribution in a space of at least a size corresponding to the area of the substrate, is required, but the planar spiral antenna does not satisfy this requirement.

In order to solve this problem, various types of antennas have been disclosed. For example, Korean Patent Appln. No. 7010807/2000 discloses a transformer-coupled planar antenna in which planar spiral antennas are arranged in parallel (refer to FIG. 3) . Further, Korean Patent Appln. No. 14578/1998 discloses a large-area planar antenna having the shape of a radial structure (refer to FIGS. 4A and 4B) . Also, Korean Patent Appln. No. 35702/1999 discloses an antenna in which parallel antennas are combined with each other (refer to FIGS. 5A and 5B) .

However, in operating these types of antennas, several problems may occur. For example, it is difficult to match input power between antennas, segmented antennas undergo problems attributable to the disturbance of electromagnetic waves formed between respective antennas, and it is difficult to manufacture the antennas. Also, when the properties of some antennas of an antenna combination are independently changed during long-term operation, the change in the properties cannot be controlled, thus deteriorating operational safety. Further, in the case of parallel antennas, since the antennas are implemented using a plurality of antenna coils, inductors or capacitors must be connected to respective lines of the parallel antennas in order to structurally adjust the phase of input currents that are flowing through the lines of the respective parallel antennas ranging from the input ports to output ports thereof. This requirement also narrows the operation window of a reactor.

Therefore, the structure of an antenna using one input port and a separate output port is ideal, but this is problematic because it is difficult to adjust plasma density in the center portion of a spiral antenna by controlling an increase in an induced electric field occurring in the center portion, thus making a non-uniform distribution or density of plasma.

[Disclosure]

[Technical Problem]

Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a magnetized, inductively coupled plasma processing apparatus and plasma generation method, which can solve a problem in that, in an inductively coupled plasma processing apparatus, it is difficult to ignite plasma and to generate and maintain high-density plasma when a gas pressure becomes low, and a problem in that, in a planar spiral antenna, plasma has a non-uniform distribution in which plasma density is high in a center portion and is rapidly decreased toward an edge due to an induced electric field.

Another object of the present invention is to provide a magnetized, inductively coupled plasma processing apparatus and plasma generation method, which can facilitate the installation of a device for forming an external magnetic field that realizes a plasma confinement effect, and which not only can easily perform a repair operation when abnormalities occur in the device, but also can form uniform plasma distribution through simple variation in shapes and arrangement. [Technical Solution]

In accordance with an aspect of the present invention to accomplish the above objects, there is provided an inductively coupled plasma processing apparatus, comprising a vacuum chamber; sample seating means provided in the vacuum chamber; an antenna configured to generate plasma in the vacuum chamber; and at least one pair of permanent magnets arranged above the antenna and below the sample seating means and configured to generate a magnetic field in a vertical direction of the vacuum chamber and to have opposite polarities on the facing ends.

Preferably, the inductively coupled plasma processing apparatus may further comprise at least one pair of side magnets arranged on a side surface of the vacuum chamber and configured to form a multipolar surface magnetic field in a direction perpendicular to an axis of the vacuum chamber. The side magnets may be arranged such that polarities of neighboring magnets are opposite each other.

Preferably, the inductively coupled plasma processing apparatus may further comprise a non-conductive window for isolating the antenna from a reaction chamber, included in the vacuum chamber for generating the plasma, and passing an induced electromotive force of the antenna therethrough. The non-conductive window may have a planar shape or a non- planar shape.

Preferably, the antenna may be located either in an upper portion of the vacuum chamber or in a reaction chamber which is included in the vacuum chamber and in which the plasma is generated.

Preferably, the permanent magnets may be arranged in any one selected from among one or more concentric circular shapes, one or more concentric rectangular shapes, and spiral shapes wound at least once, or may be arranged in any one selected from among a plurality of parallel linear shapes and one or more serpentine shapes.

Preferably the magnetic field formed in the vertical direction of the vacuum chamber may have intensity that is

0.2 to 10 times intensity of a magnetic field, by which a frequency of a radio wave applied to the antenna becomes a frequency of an electron cyclotron.

In accordance with another aspect of the present invention to accomplish the above objects, there is provided a plasma generation method performed in an inductively coupled plasma processing apparatus, comprising

(a) injecting reaction gas into a low-pressure reaction chamber toward a portion over a sample; (b) generating electromagnetic waves through the reaction gas using an antenna by which RF power is supplied; and (c) applying a magnetic field in a vertical direction of the reaction chamber using permanent magnets placed above and below the sample in order to make distribution of plasma, generated due to the electromagnetic waves, uniform and to form plasma over the sample.

Preferably, the plasma generation method may further comprise applying a multipolar surface magnetic field in a direction perpendicular to an axis of the reaction chamber using a plurality of permanent magnets mounted on a side surface of the reaction chamber.

Preferably, the multipolar surface magnetic field may be applied in the direction perpendicular to the axis of the reaction chamber using the plurality of side magnets arranged such that polarities of neighboring magnets mounted on the side surface of the reaction chamber are opposite each other. Preferably, the magnetic field applied in the vertical direction of the reaction chamber may be applied in such a way that density of magnetic flux is increased in an outward radial direction from a center of the sample.

[Advantageous Effects] As described above, the plasma processing apparatus and plasma generation method according to the present invention are advantageous in that the generation and maintenance of high-density plasma are facilitated at low pressure, and a non-uniform distribution of plasma density in a reaction chamber can be easily improved to realize uniform distribution.

Further, the present invention is advantageous in that the installation of a device for forming an external magnetic field which realizes a plasma confinement effect is simplified, and in that, when abnormalities occur in the device, a repair operation for the device can be easily performed, and, in addition, uniform plasma distribution can be formed through simple variation in shapes and arrangement .

[Description of Drawings]

FIG. 1 is a diagram showing an inductively coupled plasma generation apparatus generally used in the prior art;

FIG. 2 is a diagram showing a planar spiral antenna widely used in a conventional plasma processing apparatus;

FIG. 3 is a diagram showing a transformer-coupled planar antenna disclosed in Korean Patent Appln. No. 7010807/2000, in which planar spiral antennas are arranged in parallel;

FIGS. 4A and 4B are diagrams showing a large-area planar antenna, having the shape of a radial structure, disclosed in Korean Patent Appln. No. 14578/1998;

FIGS . 5A and 5B are diagrams showing an antenna disclosed in Korean Patent Appln. No. 35702/1999 in which parallel antennas are combined with each other;

FIG. 6 is a diagram showing the construction of an inductively coupled plasma processing apparatus according to an embodiment of the present invention;

FIGS . 7A and 7B are diagrams showing the shapes of a section of the arrangement of permanent magnets for forming an external magnetic field in an inductively coupled plasma processing apparatus according to the present invention;

FIGS. 8A and 8B are diagrams showing the shapes of a section of the arrangement of permanent magnets according to another embodiment of the present invention;

FIG. 9 is a diagram showing the construction of an inductively coupled plasma processing apparatus and the distribution of magnetic flux according to another embodiment of the present invention;

FIGS. 1OA and 1OB are diagrams showing examples of permanent magnets for forming a vertical magnetic field in a plasma processing apparatus according to the present invention, the examples showing a concentric circular shape and a spiral shape, respectively; and

FIGS. HA and HB are diagrams showing examples of permanent magnets for forming a perpendicular magnetic field in a plasma processing apparatus according to the present invention, the examples showing a concentric rectangular shape and a rectangular spiral shape, respectively.

[Best Mode]

The above and other objects and features of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings .

Preferred embodiments of the present invention will be described in detail with reference to the attached drawings. It should be noted that, in the following description of the present invention, detailed descriptions may be omitted if it is determined that the detailed descriptions of related well-known functions and construction may make the gist of the present invention unclear.

Hereinafter, a magnetized, inductively coupled plasma processing apparatus and plasma generation method according to embodiments of the present invention will be described in detail with reference to FIGS. 6 to 11.

FIG. 6 is a diagram showing the construction of an inductively coupled plasma processing apparatus according to an embodiment of the present invention. As shown in FIG. 6, the apparatus of the present invention includes a vacuum chamber 200, a sample seating means 205 provided in the vacuum chamber 200, a planar antenna 210 placed in an upper portion of the vacuum chamber 200 and configured to generate plasma, a non-conductive window 240 configured to isolate the antenna from a reaction chamber 201 so that the induced electromotive force of the antenna 210 passes through the non-conductive window 240, one or more side magnets 250 arranged on the side surface of the vacuum chamber 200 and configured to form a multipolar surface magnetic field in a direction vertical to the axis of the chamber, and at least one pair of permanent magnets 230 and 235 arranged above the antenna 210 and below the sample seating means 205 and configured to form a magnetic field in a direction parallel to the axis of the reaction chamber 201, the permanent magnets 230 and 235 having opposite polarities on the facing ends.

Here, the vacuum chamber 200 includes both a portion in which the antenna 210 is formed, and the reaction chamber 201. The vacuum chamber 200 and the reaction chamber 201 may be designated by the same name, but the reaction chamber 201 in the present invention designates a portion of the vacuum chamber 200 in which plasma is actually generated. Accordingly, in the detailed description of the present invention, the vacuum chamber 200 and the reaction chamber 201 are distinguished from each other. Of course, when the non-conductive window 240 is not present, the vacuum chamber 200 may be the reaction chamber 201.

In this case, part of the vacuum chamber 200, which exists over the non-conductive window 240 and in which the antenna is formed, may be maintained in a vacuum state or an atmospheric pressure state. In detail, the vacuum chamber 200 has a structure including the planar antenna 210 spirally wound several times, a power source (not shown) for supplying power to the antenna 210, a low-pressure reaction (etching or deposition) chamber 201, the non-conductive window (for example, a quartz window or the like) 240 for isolating the antenna from the reaction chamber 201 so that the induced electromotive force of the antenna 210 passes through the window, an electrode (not shown) for etching or deposition, the impedance matching circuit (not shown) of the antenna, a Radio Frequency (RF) power source for supplying a bias to the electrode, an RF shielding housing (not shown) for the antenna, the side magnets 250 for generating a multipolar surface magnetic field in a direction perpendicular to the axis of the chamber, and the permanent magnets 230 and 235 for generating an external magnetic field in a direction parallel to the axis of the chamber.

In this case, as shown in FIG. 6, the non-conductive window 240 may include a non-planar window, for example, a domed window, as well as a planar window.

Further, in the present embodiment, although the antenna for generating plasma is described to be a planar antenna, the shape of the antenna is not limited to the planar antenna and may include non-planar antennas . For example, a non-planar spiral antenna or a non-planar concentric circular antenna corresponding to a domed shape may be used to comply with a domed window. In this case, a plurality of concentric circular antennas may be preferably used, thus forming a non-planar shape.

Further, in the present invention, although the shape of the planar antenna is described to be of a spiral shape, antennas having other shapes, for example, a plurality of linear antennas or serpentine antennas, may be used to generate plasma. The shape of the antenna may be determined by the shape of the reaction chamber or the like. For example, when the reaction chamber has a cylindrical shape, a spiral antenna or a plurality of concentric circular antennas may be used. When the reaction chamber has a square pillar shape, a plurality of linear antennas or serpentine antennas may be used, thus generating plasma in the reaction chamber.

Hereinafter, the principles of the generation of plasma through the structure of the apparatus of FIG. 6 according to the embodiment of the present invention will be described.

Plasma, which is an aggregate of ions, electrons, and neutrals, is widely applied to energy, lighting, environments, indicators, heat sources, new substance synthesis, thin film manufacture, semiconductor etching processes, etc.. According to the purposes of application, various methods of igniting and maintaining plasma may exist. In the case of plasma used for a semiconductor etching process and a value-added thin film deposition process, a current or voltage source, such as that of an ultra-high frequency or a radio frequency, is generally used, and power is transmitted to the plasma using various mechanisms.

Therefore, the properties of plasma (electron density, electron temperature, operating pressure, ion current density, ion energy, the type and density of active species, and uniformity of plasma) are determined according to the power transmission method and the discharge form of plasma, and the success or failure of etching and deposition processes is influenced by the properties of plasma.

The inductively coupled plasma processing apparatus includes an antenna, an antenna power source, a low- pressure processing (etching or deposition) chamber isolated from the antenna by the non-conductive window (a quartz window or the like), an RF power source for a processing electrode, etc.. The inductively coupled plasma processing apparatus can obtain plasma in such a way that RF (several MHz ~ several tens of MHz) current is transmitted from the outside to the antenna through the impedance matching circuit, and an induced electromotive force passes through the externally isolated low-pressure processing chamber with a window made of a ceramic-like non-conductor, such as a quartz.

In the case of the above-described inductively coupled plasma processing apparatus, since the induced electromotive force cannot deeply penetrate into plasma generated in the processing chamber, it exists only in an area having a depth ranging from the quartz window to a location corresponding to several cm immediately below the quartz window, and this penetration depth is given by the following equation,

where ω_pe, v , c, and ω refer to a plasma frequency, a collision frequency, light velocity, and an applied RF frequency, respectively.

Therefore, in order to overcome a disadvantage in that uniform large-area plasma cannot be generated at high density because an induced electromotive force cannot deeply penetrate into the processing chamber in the conventional plasma processing apparatus, a device for magnetizing plasma has been developed to allow the induced electromotive force to deeply penetrate into the processing chamber and thus to generate high-density plasma [reference patent: Korean Patent Registration No. 10-0178847] .

Plasma can be effectively magnetized by using a planar antenna spirally wound several times and applying a magnetic field perpendicular to the antenna to the processing chamber through at least one pair of coil electromagnets .

When the plasma is magnetized by the external magnetic field, a conductivity tensor or a dielectric tensor for determining the properties of plasma is given by the following equation.

^■ n e^~ σγ=

^{X m} l^t'_m+J*⁾-+£ Cf

Hi" i

The above conductivity tensor or dielectric tensor is greatly different from electric conductivity which is obtained in the absence of a magnetic field and is given by the following equation, ne^~ i σ= m v_m + jiv

where n, e, ω, v_m , and ω_ce refer to electron density, the electron charge, the frequency of externally applied electromagnetic waves, a collision frequency, and the electron cyclotron frequency, respectively.

When the properties of plasma are changed in this way, electromagnetic waves can be transmitted into the plasma, so that the penetration depths of an induced electric field and an induced magnetic field can be increased. Further, the penetration depths can be adjusted using the intensity of a magnetic field. Therefore, the volume of plasma in which power transmission occurs is greatly increased.

The real part or the imaginary part (indicating energy absorption) of the wave number of electromagnetic waves, generated at this time, is derived from the dielectric tensor, and is a function of the collision frequency, the electron density, and the intensity of the magnetic field. A wavelength is about several to several tens of cm in an area in which the apparatus of the present invention is mainly operated (sub mTorr ~ several tens of mTorr, input power: IOOW ~ several kW, magnetic field: several ~ several tens of Gauss) . In addition, since an external magnetic field is present over the entire reaction chamber, loss of electrons in a radial direction is decreased, so that the potential of plasma is decreased, and thus the loss of ions is also decreased. As a result, uniform large-area high-density plasma can be generated.

However, in the prior art, there is a difficulty in installing one pair of coil electromagnets for forming an external magnetic field. Further, there is a problem in that, when abnormalities occur, repair or correction is not easily performed. More importantly, there is a disadvantage in that the distribution of the intensities of magnetic fields in a radial direction cannot be freely designed.

Therefore, in the present invention, in order to improve the uniformity of plasma distribution attributable to an induced electromotive force, the system is configured in such a way that at least one pair of permanent magnets, which enable the shape and arrangement thereof to be easily implemented, are arranged above and below the reaction chamber, and the shape of the permanent magnets is changed to be brought into accordance with the plasma distribution.

FIGS. 7A and 7B are diagrams showing the shapes of a section of the arrangement of permanent magnets for forming an external magnetic field in an inductively coupled plasma processing apparatus according to an embodiment of the present invention.

As shown in FIGS. 7A and 7B, when several concentric circular permanent magnets, or permanent magnets, spirally wound at least once, are arranged above and below the sample seating means so that the magnets, facing the inside of the reaction chamber, have opposite polarities, a magnetic field may be formed in a direction parallel to the axis of the chamber. The distribution of magnetic flux may vary according to at least one of the shape and arrangement method of permanent magnets, and may greatly influence the distribution of plasma.

Such a permanent magnet is a magnet for generating and maintaining a stable magnetic field without being supplied with electric energy from the outside. Compared to the permanent magnet, a magnet having very low ability to maintain a magnetized state is called a temporary magnet. For the material of the permanent magnet, a material having a high coercive force (several hundreds of Oe) , as well as high residual magnetism (about several thousands - ten thousand G) , unlike a material having high magnetic permeability, is suitable. Representative materials are Alnico (an alloy of aluminum, nickel, cobalt and copper) , CuNiFe (an alloy of copper, nickel, and Fe), Sm-Co, Nd-Fe- B, etc.

That is, a permanent magnet is a magnet in which a magnetic body itself is capable of permanently forming a magnetic field, without forming a magnetic field by being supplied with electric energy from the outside as in the case of existing coil electromagnets. The present invention not only can realize uniform plasma distribution but also can easily form an external magnetic field through the use of such permanent magnets .

Meanwhile, the principles of the formation of plasma in the reaction chamber are described below. When gas having a pressure of about sub mTorr to several hundreds of mTorr is injected into the reaction chamber, and a low voltage is applied to the antenna and is gradually increased, light is emitted from the entire area of the inside of the reaction chamber, except for nearby regions of a chamber wall and the electrode, at the same that plasma is generated from that area, at more than a certain voltage. This phenomenon is called gas discharge.

In the light emitting area, gas is ionized, and the densities of electrons and ions are rapidly increased compared to those before gas discharge occurs . The term 'discharge' means an operation in which electrons, constituting a gas atom or molecule, acquire energy from the outside and are released from the binding of the atom or molecule, thus enabling more free electrons to be continuously formed. That is, the gas atom or molecule is divided into positive ions and electrons through ionization, and an ionized gas is called a plasma. The charged particles of the ionized gas, existing in the light emitting area, have a considerably high density (about 10⁹/cm³ in a fluorescent lamp) , and are entirely maintained in an electrical neutral state.

In the plasma, the average density of electrons is identical to that of ions (the density of neutrals is much greater than the above average densities) , and is called plasma density. An area of a thin layer in which light is not emitted exists around the plasma, and looks as if the area encloses the plasma. This area is called a sheath. In the sheath, ionization attributable to electrons scarcely occurs because electrons are exhausted. Therefore, the charged particles have a low density and are not electrically neutral, and glow is not observed in the sheath. The sheath is formed in all contact entities, such as a positive electrode, conductors, and insulators which are exposed to plasma, as well as a negative electrode.

On the basis of these principles, in the plasma processing apparatus of the present invention, permanent magnets are arranged on the side surfaces or on the top of the reaction chamber 201 and on the outer side of the bottom of the reaction chamber 201, as shown in FIG. 6, thus enabling magnetic force lines generated by the permanent magnets 230, 235 and 250 to be formed in an optimal shape in the reaction chamber.

The top permanent magnets 230 and the bottom permanent magnets 235, facing the inside of the reaction chamber 201, are designated to have opposite polarities, so that magnetic force lines can be formed in the reaction chamber 201 straight along the axial direction of the reaction chamber 201. Meanwhile, when side magnets 250 are permanent magnets, the polarities of neighboring magnets facing the inside of the reaction chamber 201 may alternate with each other, so that a plasma confinement effect is realized by a multipolar surface magnetic field, thus increasing plasma density by reducing plasma loss in the chamber, and improving the uniformity of plasma density in a radial direction. The magnetic force lines generated by the top permanent magnets 230 and the bottom permanent magnets 235 have radial components of the reaction chamber 201, as well as having the axial components of the reaction chamber 201.

Such radial components cause the Jz y JJ drift motion of electrons through the axial electric field and radial magnetic field of the reaction chamber 201 in the sheath, improves uniformity in a rotational direction and a radial direction of the reaction chamber 201, and promotes an ionization reaction. FIGS. 8A and 8B are diagrams showing the shapes of a section of the arrangement of permanent magnets according to another embodiment of the present invention. As shown in FIG. 8A, permanent magnets are arranged using several concentric rectangles, and the section thereof has the shape of several concentric rectangular loops. This shape enables the distribution of electrons or ions in the radial direction to be uniform, like the concentric circular permanent magnets shown in FIGS. 7A. FIG. 8B illustrates a permanent magnet arranged in the shape of a meander line. This is a structure enabling the intensity of a magnetic field formed in the vertical direction of the reaction chamber 201 to be uniform in the radial direction through the shape in which the permanent magnet is wound at least once. It is apparent that this structure can be formed to have various symmetric structures in the radial direction, unlike the shape exemplified in the drawings. Further, in the arrangement of a plurality of concentric or spiral permanent magnets, when the permanent magnets have a shape in which an interval therebetween is narrowed in an outward radial direction, the density of magnetic flux is increased in the outward radial direction, thus realizing the effects of the improvement of uniformity of plasma distribution (not shown) .

In this case, the top and bottom permanent magnets may be arranged in shapes other than the shapes of FIGS. 7A and 7B and FIGS. 8A and 8B. For example, a plurality of linear permanent magnets may be arranged in parallel or in a lattice shape, for example, the shape of a rectangular lattice or a honeycomb (hexagonal) lattice.

Further, the shape of the arrangement of the top and bottom permanent magnets may differ according to the shape of the reaction chamber. For example, when the reaction chamber is a cylindrical chamber, a plurality of concentric or spiral permanent magnets is used, as shown in FIGS. 7A and 7B. When the reaction chamber is a square pillar chamber, any one selected from among rectangular permanent magnets and meander line-shaped permanent magnets, as shown in FIGS. 8A and 8B, a plurality of linear permanent magnets, and a plurality of lattice-shaped permanent magnets can be used. Of course, the density of the arrangement of permanent magnets may vary so as to improve the uniformity of plasma processing in the center and surrounding portions of the reaction chamber. The top permanent magnets and the bottom permanent magnets preferably have opposite polarities and face the inside of the reaction chamber.

At this time, the shape and arrangement of the top and bottom permanent magnets may vary according to the intensity of a vertical magnetic field in the reaction chamber. The intensity and location of permanent magnets can be selected so that the vertical magnetic field has intensity that is 0.2 to 10 times the intensity of a magnetic field, by which the frequency of a radio wave applied to the apparatus becomes the electron cyclotron

frequency, that is, B = —2ττf (where B, m, e, and f refer to e the intensity of the magnetic field, mass of electron, charge, and frequency of radio wave, respectively) .

Here, when radio waves having separate frequencies are applied to the antenna and a substrate support, the frequency f, required to calculate the intensity of a magnetic field, is preferably implemented using the frequency of a radio wave having the highest power.

FIG. 9 is a diagram showing the construction of an inductively coupled plasma processing apparatus and the distribution of magnetic flux according to a further embodiment of the present invention.

As shown in FIG. 9, the apparatus of the present invention includes a vacuum chamber 300, a sample seating means 305 provided in the vacuum chamber 300, a planar antenna 310 placed on the vacuum chamber 300 and configured to generate plasma, a non-conductive window 340 configured to isolate the antenna from a reaction chamber 301 so that the induced electromotive force of the antenna 310 passes through the non-conductive window 340, side magnets 350 arranged on the side surface of the vacuum chamber 300 and configured to form a multipolar surface magnetic field in a direction perpendicular to the axis of the chamber, and at least one pair of concentric or spiral permanent magnets 330 and 335 arranged above the antenna 310 and below the sample seating means 305, and configured to form a magnetic field in a direction parallel to the axis of the vacuum chamber 300 and to have opposite polarities on the facing ends, the permanent magnets 330 and 335 being arranged thickly or densely in a direction away from the center, with regard to the section thereof.

In this case, the side magnets 350 may be either electromagnets or permanent magnets. The side magnets may be implemented such that, as described above, the polarities of neighboring magnets facing the inside of the reaction chamber may alternate with each other, so that a plasma confinement effect is realized by a multipolar surface magnetic field, thus increasing plasma density by reducing plasma loss in the chamber, and improving the uniformity of plasma density in the radial direction.

Further, the top and bottom permanent magnets 330 and 335 are arranged such that a magnetic field is formed in a direction from the top to the bottom by causing the polarities thereof to be opposite each other on the facing ends. In addition, the top and bottom permanent magnets have shapes in which they are arranged thickly or densely in the radial direction of the section of the magnets in order to solve the problem of non-uniform plasma distribution of the prior art in that plasma density is high at the center and is rapidly decreased toward the edge.

FIGS. 1OA and 1OB are diagrams showing examples of permanent magnets for forming a vertical magnetic field in the plasma processing apparatus of the present invention, the examples showing concentric or spiral shapes, respectively. As shown in FIGS. 1OA and 1OB, the examples are characterized in that the thickness of the section of the permanent magnets corresponding to that of FIGS. 7A and 7B is increased in a direction away from the center, and the shape of the section is a circle. FIGS. HA and HB are diagrams showing other examples of permanent magnets for forming a vertical magnetic field in the plasma processing apparatus of the present invention, the examples showing a concentric rectangular shape and a rectangular spiral shape, respectively. As shown in FIGS. HA and HB, the examples are characterized in that the thickness of the section of the permanent magnets corresponding to that of FIGS. 8A and 8B is increased in a direction away from the center, and the shape of the section is a rectangle.

Any shapes symmetrical in a radial direction to the shape of a sample can be used, and the shapes of permanent magnets are not limited to the embodiments shown in the drawings. That is, when the density of magnetic flux is increased at the edge of the sample, the intensity of a

magnetic field per unit area is increased, and the JC<X 13 drift motion of electrons or ions is increased because of the interaction between an electric field and a magnetic field in this edge region. Accordingly, the density of plasma is increased, thus realizing a uniform plasma distribution over the entire area of the sample.

It is apparent that the shape of the section of permanent magnets may be of other shapes suitable for improving the uniformity of plasma distribution, as well as being of the shapes given as examples .

A detailed description of the present invention has been made on the basis of embodiments in which the antenna for generating plasma is placed above the non-conductive window isolated from the reaction chamber, but the structure of the present invention is not limited by these embodiments. Those skilled in the art will appreciate that the antenna may be provided in the reaction chamber in which plasma is actually generated. As described above, a magnetized, inductively coupled plasma processing apparatus and plasma generation method according to the present invention can be modified or applied in various forms within the scope of the technical spirit of the present invention, and are not limited to the above embodiments. Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that they are not intended to limit the scope of the technical spirit of the invention, and various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. The scope of the present invention must be defined by the accompanying claims and equivalents thereof.

ΪMbde for Invention]

[industrial Applicability] As described above, a plasma processing apparatus and plasma generation method according to the present invention are advantageous in that the generation and maintenance of high-density plasma are facilitated at low pressure, and a non-uniform distribution of plasma density in a reaction chamber can be easily improved to realize uniform distribution.

Claims

[CLAIMS] [Claim l]

An inductively coupled plasma processing apparatus, comprising: a vacuum chamber; sample seating means provided in the vacuum chamber; an antenna configured to generate plasma in the vacuum chamber; and at least one pair of permanent magnets arranged above the antenna and below the sample seating means and configured to generate a magnetic field in a vertical direction of the vacuum chamber and to have opposite polarities on the facing ends .

[Claim 2] The inductively coupled plasma processing apparatus according to claim 1, further comprising at least one pair of side magnets arranged on a side surface of the vacuum chamber and configured to form a multipolar surface magnetic field in a direction perpendicular to an axis of the vacuum chamber.

[Claim 3]

The inductively coupled plasma processing apparatus according to claim 2, wherein the side magnets are electromagnets or permanent magnets .

[Claim 4] The inductively coupled plasma processing apparatus according to claim 2, wherein the side magnets are arranged such that polarities of neighboring magnets are opposite each other.

[Claim 5]

The inductively coupled plasma processing apparatus according to claim 1, further comprising a non-conductive window for isolating the antenna from a reaction chamber, included in the vacuum chamber for generating the plasma, and passing an induced electromotive force of the antenna therethrough .

[Claim β]

The inductively coupled plasma processing apparatus according to claim 5, wherein the non-conductive window has a planar shape or a non-planar shape.

[Claim 7]

The inductively coupled plasma processing apparatus according to claim 1, wherein the antenna is a planar antenna or a non-planar antenna .

[Claim 8]

The inductively coupled plasma processing apparatus according to claim 1, wherein the antenna is located either in an upper portion of the vacuum chamber or in a reaction chamber which is included in the vacuum chamber and in which the plasma is generated .

[Claim 9]

The inductively coupled plasma processing apparatus according to claim 1, wherein the permanent magnets are arranged in any one selected from among one or more concentric circular shapes, one or more concentric rectangular shapes, and spiral shapes wound at least once.

[Claim lθ]

The inductively coupled plasma processing apparatus according to claim 9, wherein at least one of a thickness and a height of the permanent magnets is increased in a direction away from a center of the vacuum chamber.

[Claim 11]

The inductively coupled plasma processing apparatus according to claim 9, wherein an interval between the permanent magnets is narrowed in a direction away from a center of the vacuum chamber.

[Claim 12]

The inductively coupled plasma processing apparatus according to claim 1, wherein the permanent magnets are arranged in any one selected from among a plurality of parallel linear shapes and one or more serpentine shapes.

[Claim 13] The inductively coupled plasma processing apparatus according to claim 1, wherein the magnetic field formed in the vertical direction of the vacuum chamber has intensity that is 0.2 to 10 times intensity of a magnetic field, by which a frequency of a radio wave applied to the antenna becomes a electron cyclotron frequency.

[Claim 14]

The inductively coupled plasma processing apparatus according to claim 1, wherein the permanent magnets have cylindrical shapes or hexahedral shapes.

[Claim 15]

A plasma generation method performed in an inductively coupled plasma processing apparatus, comprising: (a) injecting reaction gas into a low-pressure reaction chamber toward a portion over a sample;

(b) generating electromagnetic waves through the reaction gas using an antenna by which RF power is supplied; and (c) applying a magnetic field in a vertical direction of the reaction chamber using permanent magnets placed above and below the sample in order to make distribution of plasma, generated due to the electromagnetic waves, uniform and to form plasma over the sample.

[Claim 16] The plasma generation method according to claim 15, further comprising applying a multipolar surface magnetic field in a direction perpendicular to an axis of the reaction chamber using a plurality of permanent magnets mounted on a side surface of the reaction chamber.

[Claim 17]

The plasma generation method according to claim 16, wherein the multipolar surface magnetic field is applied in the direction perpendicular to the axis of the reaction chamber using electromagnets or permanent magnets mounted on the side surface of the reaction chamber.

[Claim 18]

The plasma generation method according to claim 16, wherein the multipolar surface magnetic field is applied in the direction perpendicular to the axis of the reaction chamber using the plurality of side magnets arranged such that polarities of neighboring magnets mounted on the side surface of the reaction chamber are opposite each other.

[Claim 19] The plasma generation method according to claim 15, wherein the magnetic field applied in the vertical direction of the reaction chamber is applied in such a way that density of magnetic flux is increased in an outward radial direction from a center of the sample.