JP2965169B2 - Microwave discharge reaction device and electrode device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microwave discharge reactor and an electrode device, and more particularly to a microwave discharge reactor suitable for application to a dry etching device, a plasma CVD device, a sputtering device, a surface reforming device, and the like. The present invention relates to an electrode device.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Patent Application Laid-Open No. 55-141729.
(Electron Cyclotron Resonance) disclosed in Japanese Patent Publication
Various devices have been proposed for a discharge reaction device using an electromagnetic wave in a microwave region, such as a device. Generally, in order to efficiently generate plasma in a discharge chamber in this type of discharge reaction apparatus, it is necessary to design the discharge chamber such that the discharge chamber acts as a resonator with respect to the frequency of a microwave to be used. Therefore, the size of the discharge chamber is approximately equal to the wavelength of the microwave (approximately 1.
The size is limited by 2 cm), and if the discharge chamber is simply enlarged, plasma becomes non-uniform due to the generation of standing waves in higher-order modes, and a substrate having a large area is processed with good uniformity. That was impossible.

On the other hand, the size of a substrate to be processed has been increasing in recent years, and it has become necessary to process a substrate having a size several times the wavelength of a microwave of 2.45 GHz with good uniformity. Further, a conventional discharge reaction apparatus generally employs a structure in which a microwave is introduced into a discharge chamber using a waveguide.
Since the size of the waveguide is determined depending on the frequency region to be used, dimensional restrictions in the design of the device are large, and the reliability of the window for introducing microwave is not sufficient.

On the other hand, a coaxial tube is used for introducing microwaves, and a cylindrical electrode having a large number of slits is used as an antenna for radiating microwaves. Is also being developed. This device is, for example, A.Yonesu etal. Production of a larg
e-diameter uniform ECR plasma with a Lisitanocoil "
Jpn. J. Appl. Phys., 27 (1988) L1746.). Also, as disclosed in JP-A No. 1-1593 79 JP,
Attempts have been made to uniformly treat a large area by using a plate-like electrode having a large number of slits as an antenna.

[0005]

By the way, in order to generate plasma with good uniformity over a large area using the cylinder having a large number of slits as an electrode, ECR conditions, that is, 2.45 GHz, are required throughout the cylinder. For a microwave, it is necessary to generate a magnetic field having a magnetic flux density of 875 gauss in a direction parallel to the slit. For example, to process a substrate with a diameter of 300 mm with good uniformity, the above-mentioned A. Yo
nesu et al. According to the reference, it is necessary to use a cylindrical electrode having an inner diameter of 400 mm. 8 inside such a large electrode
In order to generate a magnetic field of 75 Gauss with good uniformity, a huge air-core coil is required, and this has been a major obstacle in putting a discharge reactor using the cylindrical electrode into practical use.

[0006] Also in the discharge reaction device using the plate-shaped electrodes having a plurality of slits as disclosed in the JP-A 1-1593 79 JP as an antenna, also large in order to generate a magnetic field of the electrode and the vertical direction An air-core coil is required, and the conventional configuration that does not use such an air-core coil does not provide good plasma generation efficiency.

As an example of a solution to the above drawback, one of the present inventors (Nakagawa) has previously filed an application in which an individual permanent magnet is installed for each slit (Japanese Patent Application No. Hei. No.-9356).

Further, a drawback common to the above three types of conventional apparatuses is that the magnetic field used to generate plasma is continuous up to the area where the substrate to be processed is installed, so that the magnetic field in the plasma generation area is low. The non-uniformity of the plasma density due to the condition and the standing wave is directly reflected in the distribution of the ion current density on the substrate to be processed, which is an obstacle to performing a uniform processing. In addition, since the trajectory of ions incident on the substrate follows the direction of the magnetic field, the uniformity of the magnetic flux density over the entire surface of the substrate is particularly large when performing fine processing by dry etching utilizing the reactivity of ions. It is necessary to arrange the coils so that the direction of the magnetic field is also vertical over the entire surface of the substrate to be processed. This state is generally impossible with a single air-core coil, and the configuration of a micromagnetic discharge reactor becomes very complicated. Recently proposed discharge reactor using plasma near the ECR condition region (S. Samukawa
et al. “Extremely high-selective electron cyclot
ron resonance plasma etching for phosphorus-doped
polycrystaline silicon. ”Appl.Phys.Lett.57 (1990) 4
Even in 03.), the above problems have not been essentially solved.

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to produce a plasma with good uniformity, which does not require a huge air-core coil, can be manufactured simply and inexpensively with a simple configuration, In addition, the generation efficiency is good, and a highly practical microwave discharge reactor capable of uniformly processing a substrate having a large area, and an electrode suitable for realizing the microwave discharge reactor. Device.

[0010]

A microwave discharge reaction apparatus according to the present invention comprises a vacuum vessel having a mechanism for maintaining the inside of the reactor under reduced pressure and a mechanism for introducing a gas, and introducing a microwave into the vacuum vessel. A microwave discharge reaction device comprising a plasma generating mechanism for converting a gas into plasma, and a substrate holding mechanism provided at an interval from the plasma generating mechanism. A coaxial transmission line to be introduced into the electrode inside the container, a flat electrode having at least one slit of a predetermined length and width for radiating microwaves, and a radial radial slit disposed in the vicinity of the flat electrode. is constituted by a magnetic field generating means for generating a magnetic field close to the same direction as the longitudinal direction of the part, the microwave radiated into the vacuum vessel by the electrode , And generating a plasma in front space of the substrate holding apparatus by an interaction between a magnetic field generated in a direction perpendicular to the electric field of the microwave by the magnetic field generating means.

[0011] In the above microwave discharge reactor,
The radial radial portion of the slit formed in the electrode is radially arranged from the center of the electrode, and the magnetic field generating means is on a concentric circle sharing the center with the electrode, and the direction of the magnetic field is perpendicular to the electrode on the electrode surface. It is characterized by a plurality of cylindrical permanent magnets arranged such that

[0012] In the above microwave discharge reactor,
A target for performing dielectric sputtering is provided on a surface of the plasma generation mechanism where plasma is generated.

In the above microwave discharge reactor,
A mechanism for moving at least one of the substrate to be processed and the magnetic field generating means is provided.

An electrode device according to the present invention comprises: a flat electrode having at least one slit having a predetermined length and width to receive a microwave and emit the microwave;
It is characterized by comprising a magnetic field generating means arranged in the vicinity of the electrode to generate a magnetic field in the same direction as the length direction of the slit.

In the above electrode device, the slit is arranged radially from the center of the electrode, and the magnetic field generating means is on a concentric circle sharing the center with the electrode, and the direction of the magnetic field is perpendicular to the electrode on the electrode surface. It is characterized by being a plurality of cylindrical permanent magnets arranged in such a manner.

In the above-mentioned electrode device, the electrodes are composed of an external electrode and an internal electrode with a slit positioned therebetween.

[0017]

In the microwave discharge reaction device according to the present invention, a flat electrode having a slit having a predetermined form is provided.
A plurality of cylindrical permanent magnets are installed on concentric circles as means for efficiently radiating microwaves into the discharge chamber and simultaneously generating a magnetic field satisfying the ECR conditions. The magnetizing directions of these permanent magnets are perpendicular to the electrodes, and are arranged such that the magnetizing directions of the adjacent cylindrical permanent magnets are opposite to each other.
At this time, the magnetic field strength is set so as to satisfy the ECR condition in the vicinity of the plane of the plate-like electrode where plasma is generated.
With this configuration, it is possible to efficiently and uniformly generate plasma only in a very small area near the surface of the electrode. Furthermore, the magnetic circuit in the microwave discharge reaction device according to the present invention, that is, the magnetic field by the permanent magnet,
Unlike the magnetic field generated by the air-core coil, the range of the magnetic field is limited only to the vicinity of the electrode, so that the substrate to be processed, which is installed in a place where the magnetic field is very weak, has good uniformity independent of the shape of the magnetic field. Surface treatment can be performed.

The electrode device according to the present invention is an electrode device applied to the microwave discharge reaction device, and functions as a component that exerts its function in the microwave discharge reaction device.

[0019]

Embodiments of the present invention will be described below with reference to the accompanying drawings. In this embodiment, first, an embodiment relating to the configuration of the electrode and the magnetic circuit will be described with reference to FIGS. 1 to 6, and then, according to FIGS. 7 to 9, the configuration of the microwave discharge reaction apparatus using the electrode and the magnetic circuit will be described. An embodiment will be described.

FIG. 1 is a plan view showing an electrode and a magnetic circuit applied to a microwave discharge reactor, and FIG. 2 is a sectional view taken along the line II-II in FIG. 1 for explaining a sectional structure of the electrode and the magnetic circuit. Yes, the configuration of the electrodes and the magnetic circuit will be described with reference to FIGS. Reference numeral 1 denotes an electrode formed by processing a slit 2 on a flat plate made of a conductive material such as a metal. The electrode 1 is an external electrode 3 located at a position sandwiching the slit 2.
And the internal electrode 4. In practice, the external electrode 3 and the internal electrode 4 are made from one metal plate. The slit 2 is divided into the following three parts according to its form. One is a circular electrode 1
Slit part 2 radially extending radially from the center of
The other one is two kinds of circumferential slit portions connecting the radial slit portions 2A, that is, a slit portion 2B connecting the radial slit portions 2A with a small radius near the electrode center, and a large slit portion near the electrode periphery. It is a slit portion 2C connected by a radius. In this embodiment, the slit 2
Is a gap having a uniform predetermined width formed when the external electrode 3 and the internal electrode 4 are combined. The external electrode 3 and the internal electrode 4 are assembled so as to form this gap. In FIG. 1, members for assembling the external electrodes 3 and the internal electrodes 4 are not shown. The width of the slit 2, that is, the width of the gap between the external electrode 3 and the internal electrode 4 is actually determined to be an optimum value by an experiment, but needs to be sufficiently shorter than the wavelength (λ) of the microwave. is there. The length of the slit 2 is also set to an optimum value based on experiments. The length of the radial slit portion 2A is (n / 2) λ (where
λ is the wavelength of the microwave and n is a positive integer of 1 or more), and good results can be obtained. Although the number of radial slit portions 2A is eight in this embodiment, it can be arbitrarily determined according to the form of the electrode 1, and at least one is sufficient.

For supplying microwaves to the electrode 1, a coaxial line 6 is used as shown in FIG. In the coaxial line 6, power is supplied by connecting the center conductor 6 </ b> A to the center of the internal electrode 4 and grounding the external electrode 3. A magnetic circuit 5 composed of a plurality of cylindrical or ring-shaped permanent magnets is disposed at a slight distance from a portion of the electrode 1 to which the microwave is supplied. It is fixed to the lower surface of the flat plate 7. The plurality of cylindrical permanent magnets have different diameters and are arranged concentrically.
The positions of the N pole and the S pole in each of the permanent magnets are alternately reversed. It should be noted that the configuration shown in FIG. 2 is conceptual, and any known structure for the specific coupling structure of the coaxial line 6 and the mounting structure of the magnetic circuit 5 can be adopted. The operation of the magnetic circuit 5 will be described later in detail.

FIG. 3 shows another embodiment of the electrode.
In the present embodiment, a rectangular electrode 11 was formed by processing a plurality of slits 10 in one metal flat plate. One slit 10 is composed of a radial slit portion 10A and two types of slit portions 10B and 10C having different circumferential radii. In this case, one slit 1
The total length of 0 is ((2n-1) / 2) λ (where λ is the wavelength of the microwave and n is a positive integer of 1 or more), and the midpoint of the slit 10 is the center of the electrode 11. The configuration is as follows. In the above configuration, the coaxial line (or the
When the center conductor 6A of the axial tube 6 is connected to the center point of the radial slit portion 10A, a microwave standing wave is generated along the slit 10, so that the plasma generation efficiency can be particularly improved.

Next, conditions regarding the thickness required for the electrodes 1 and 11 will be described. The electrodes described in the above two embodiments do not cause any functional problem even if the electrodes are very thin. The reason for this is that the microwave current concentrates on a very thin surface layer given as the skin thickness. The thickness (δ) is given by the following equation.

Δ = (2 / ωμ ₀ σ) ^0.5 where ω is the angular frequency of the flowing current, μ ₀ is the magnetic permeability of the material metal, and σ is the conductivity of the metal. The microwave loss in a metal film having a thickness of several times or more of δ is equivalent to an infinitely thick plate. In the above formula, the frequency 2.45GH
Substituting copper values for z, μ ₀ and σ gives δ 0.01
mm. Therefore, it is clear that even if the thickness of the metal plate forming the electrodes 1 and 11 is very thin, there is no problem in function.

FIG. 4 is a sectional view of a main part of an electrode according to still another embodiment. In this embodiment, a metal film 13 is formed on a dielectric plate 12, and a slit 14 is formed by using the metal film 13.
This is an example in which is formed. In order to produce the metal film 9, techniques such as electroless plating, vacuum deposition, ion plating, and sputtering can be used. In order to form the slit 14 using the metal film 13, for example, after the metal film 13 is formed on the entire surface of the dielectric plate 12, a portion requiring conductivity, that is, the slits 14 in the embodiment of FIGS. After applying an acid-resistant substance such as resin to only the portion corresponding to the shape of the electrode plate shown,
An unnecessary portion of the metal film 13 may be removed with an acid or the like. It is sufficient that the thickness of the metal film 13 is about the above-mentioned value of δ (about several times of δ even when safety is expected). As the material of the dielectric plate 12, any material can be used as long as the material has good insulation properties and low dielectric loss, such as quartz and alumina.

Next, the operation of the magnetic circuit 5 will be described in detail with reference to FIGS. The operation of the magnetic circuit 5 is shown in FIGS.
This is common to all embodiments of each electrode shown in FIG. 5 and 6 are partially enlarged views of the magnetic circuit 5 and the slit 2. FIG. 5 is a plan view of a part of the electrode as viewed from the side opposite to the place where the magnetic circuit is provided. FIG. FIG. 5A, 5B and 5C show cross sections of cylindrical permanent magnets constituting a magnetic circuit. Numeral 15 indicates the state of the lines of magnetic force generated by the permanent magnets 5A to 5C. Numeral 16 indicates the direction of the electric field of the microwave radiated from the slit portion 2A on the electrode 1 (or 11). Since the direction of the electric field is reversed according to the measurement time, it is indicated here by two arrows in opposite directions.

As is apparent from FIGS. 5 and 6, the magnetic field on the slit 2 and the electric field generated by the microwave are orthogonal to each other in the vicinity of the slit.
If the conditions are satisfied, the electrons in the plasma
Since heating is performed by R, high-density plasma is efficiently generated. For example, if a magnetic field satisfying the ECR condition exists in a region 17 in FIG. 6, high-density plasma is generated in this region. This high-density plasma region 17 is
Generated in the immediate vicinity of the surface of

In each of the above embodiments, the feature of the magnetic circuit of the present invention is that a plurality of cylindrical (or ring) -shaped permanent magnets having different diameters and magnetic pole directions are coaxially arranged and used. That is, a closed magnetic field is generated on the electrode 1. Thereby, the plasma generated on the electrode 1 is diffused only in the circumferential direction, and the diffusion in the radial direction crossing the magnetic field is reduced, so that the density can be increased and the power use efficiency can be improved. This point is one of the inventors of the present application (Nakagawa)
Has previously invented and applied for another invention (Japanese Patent Application No. 2-9356).
No.) in principle.

Another operational feature of the present invention is that the magnetic field exists only near the slit 2 of the electrode 1. Conventionally, this type of apparatus generally generates a magnetic field that satisfies ECR conditions using a magnetic field generated by an air-core coil.
The high-density plasma generated in the portion satisfying the R condition was diffused along the magnetic field created by the air-core coil. Further, the ECR apparatus disclosed in Japanese Patent Application Laid-Open No. 55-141729 cited in the section of "Prior Art" aims to use plasma diffused along a magnetic field rather positively.
In contrast to these device configurations, the above-described electrode and magnetic circuit according to the present embodiment have the following features.

1. High-density plasma is localized near the electrode,
For this reason, utilization efficiency of microwave power is improved.

2. Plasma that has escaped the constraint of the magnetic field diffuses freely, so that a plasma with a large volume and good uniformity can be generated.

3. Since the movement of the ions is not restricted by the magnetic field except in the vicinity of the electrodes, the energy of the ions incident on the substrate can be electrostatically controlled.

4. In this type of apparatus, high-speed processing can be performed because a large amount of neutral active species, which plays an important role together with ions, can be generated by high-density plasma.

5. The amount of neutral active species and the incident energy of ions can be controlled independently, and it can meet various requirements in processing.

6. Because uniform plasma is used by free diffusion without using a magnetic field, uniform processing over a large area can be performed with good uniformity.

Next, a description will be given of a microwave discharge reaction apparatus utilizing the configuration of the electrodes and the magnetic circuit. FIG. 7 is a sectional view showing the internal configuration of the microwave discharge reaction device according to the present invention . Reference numeral 20 denotes a vacuum vessel used as a microwave discharge reaction apparatus. The vacuum vessel 20 has a substrate holder 21 on the lower side in the vessel and a reactive gas introduction mechanism 22 on the outside.
Is provided. Further, the electrode 1 and the magnetic circuit 5 described above are installed in the vacuum container 20 on the upper side in the container. Substrate holder 21
The lower part of the vacuum container 2 is in a floating potential state via an insulator 23.
The substrate 24 is fixed on the bottom wall of the base plate 0 and the upper surface thereof. A power supply line from a power supply 25 provided outside the vacuum vessel 20 is connected to a lower end of the substrate holder 21.

The operation of the microwave discharge reactor having the above configuration will be described. In order to operate the discharge reactor, a predetermined gas is introduced from the reactive gas introduction mechanism 22 through the valve 27 into the vacuum vessel 20 after the inside of the vacuum vessel 20 is evacuated to a required vacuum state by the exhaust system 26. I do. Next, a predetermined gas pressure is obtained by appropriately adjusting the gas flow rate and the exhaust speed by the exhaust system 26. The gas pressure at this time is usually desirably about 10 ^-6 Pa.
Microwave discharge is generated in the vacuum vessel 20 under such conditions. A microwave is supplied to the electrode 1 through the coaxial line 6 from a microwave power supply mechanism including a microwave circuit element such as an isolator, a power monitor, and a tuner. The outer conductor 6 </ b> B of the coaxial line 6 penetrates the upper wall of the vacuum vessel 20 while maintaining the vacuum sealed state, and extends to the vicinity of the electrode 1. Further, in order to maintain the degree of vacuum in the vacuum vessel 20, an insulator 29 having a vacuum sealing action is provided with a coaxial cable.
It is provided inside the road 6.

With the above configuration, the microwave is supplied to the electrode 1 via the coaxial line 6 and radiated into the inner space of the vacuum vessel 20 by the action of the slit 2 having the structure shown in FIGS. An oscillating electric field is generated. Vacuum container 2
The reactive gas introduced into 0 is ionized by the electrons accelerated by this electric field, and becomes a plasma state. The electrons in the plasma are heated resonantly by the interaction between the electric field and the magnetic field (heating by the ECR action), and ionize other neutral particles one after another to generate high-density plasma. A discharge reaction can be performed using this plasma.

The substrate holder 21 on which the substrate 24 to be processed is placed is desirably placed in a region where the magnetic field generated by the magnetic circuit 5 is sufficiently weak. If the substrate 24 requires heating, cooling, or the like according to the intended processing, a heating / cooling mechanism may be incorporated in the substrate holder 21. When various biases are applied for the purpose of controlling the amount of charged particles incident on the substrate 24 and the incident energy, an arbitrary bias such as DC or AC may be applied to the substrate holder 21 by the power supply 25. it can. When a high frequency is used as the bias, it is desirable to include a matching circuit in the power supply 25.

A feature of the microwave discharge device according to the above embodiment is that high-density plasma generated by ECR is generated only in the vicinity of the electrode 1 and most of the microwave power is absorbed. Is that the usage efficiency is high. In contrast to the conventional apparatus that generates plasma in the entirety of a large vacuum vessel, the apparatus according to the present embodiment enables surface treatment of a large-area substrate using a small volume of plasma. It is possible to reduce the size of the microwave power source that occupies a large part of the power supply.

As another characteristic, according to the present embodiment, the magnetic field for generating the plasma only needs to be present very close to the discharge electrode. This is based on the fact that the portion where the microwave oscillating electric field exists is localized only in the vicinity of the electrode by the antenna. In a conventional so-called ECR device, ions are accelerated using a divergent magnetic field generated by an air-core coil to guide ions on a substrate. Therefore, the ion density distribution on the substrate and the traveling direction of the ions are determined by the shape of the magnetic field. Was. It is difficult to generate a completely uniform magnetic field with an air-core coil, which has determined the limit of the fine processing performance of an ECR etching apparatus. On the other hand, according to the present embodiment, the magnetic field is very weak near the substrate to be processed, and does not substantially affect the movement of ions. Therefore, ions in the plasma generated in the vicinity of the electrode are incident on the substrate to be processed by free diffusion which is not affected by the magnetic field, so that uniform processing can be performed regardless of the shape of the magnetic field.

As other advantages, since the magnetic circuit 5 is a simple one using a permanent magnet, the cost is low, and the running cost is lower than that of an air-core coil that consumes a large amount of power. In addition, ions that enter the substrate are not accelerated by the magnetic field due to the use of plasma by free diffusion, and the acceleration voltage of the ions incident on the substrate has a value as low as the space potential of the plasma. This means that film deposition or etching with less irradiation damage can be performed. In addition, for a process in which good results can be obtained by irradiation of ions accelerated to some extent, such as etching of a certain material, a DC or AC bias including a high frequency is applied to the substrate holder 21 of the substrate 24 to be processed. By giving, it is possible to perform ion irradiation at an arbitrary acceleration voltage independent of parameters such as the magnetic field strength and the applied power.

In the above microwave discharge reactor,
The configuration can be changed as follows. A target may be arranged in a region where the plasma is generated. This makes it possible to perform dielectric sputtering. Further, one or both of the magnetic circuit 5 for generating a magnetic field and the substrate to be processed 24 may be configured to rotate or reciprocate. According to this configuration, the uniformity of processing on the processing target substrate 24 can be further improved. The above configuration can be similarly applied to the microwave discharge reaction device in each embodiment described below.

FIG. 8 is a sectional view showing the internal structure of another embodiment of the microwave discharge reaction device. The same elements as those described in the above embodiment are denoted by the same reference numerals. Vacuum container 3
Reference numeral 0 differs from the vacuum container 20 of the embodiment shown in FIG. The window 31 has a structure in which a vacuum is maintained by an O-ring 32. The present embodiment is characterized in that the plasma generating mechanism placed in the vacuum vessel in the previous embodiment, that is, the electrode 1 and the magnetic circuit 5 are provided outside the vacuum vessel 30. That is, as shown in FIG. 8, the electrode 1 is installed on the air side of the window 31. 33 is a metal shield plate for preventing microwaves from leaking to the atmosphere side,
Part of the shield plate 33 also serves as the conductive flat plate 7 having the magnetic circuit 5. The magnetic circuit 5 is arranged above the shield plate 33. For other configurations, see FIG.
Is substantially the same as the configuration shown in FIG.

The operation of this embodiment will be described. Substrate holder 21 attached to microwave discharge reactor, exhaust system 2
6. The configuration and operation of the reactive gas introduction mechanism 22 and the microwave power supply mechanism 28 are the same as those of the embodiment shown in FIG. The microwave power supplied to the electrode 1 is radiated from the slit 2 having the same structure as that of the electrode 1 shown in FIG. 1 and transmitted through the window 31 to generate an oscillating electric field in the vacuum vessel 30 as in the above embodiment. Similarly, the magnetic field generated by the magnetic circuit 5 passes through the window 31 and generates a magnetic field in the vacuum chamber 30. So window 3
If a magnetic field having an intensity that satisfies the ECR condition is formed on the vacuum side 1 and the intensity of the microwave electric field is sufficiently strong, high-density plasma similar to that described with reference to FIG. At this time, the condition of the window 31 is that it is required to be non-magnetic, to be an insulator, to have a small dielectric loss, to have strength to withstand the pressure difference between the atmospheric pressure and vacuum, and to be used as a material for vacuum. What you can do (specifically,
That the vapor pressure is low and vacuum sealing can be performed). As a material satisfying these conditions, ceramics such as alumina and beryllia, quartz glass, and ethylene tetrafluoride resin can be used.

An advantage of this embodiment is that since the electrode 1, the magnetic circuit 5, and the coaxial line 6 are all installed in the atmosphere, the structure of vacuum sealing becomes extremely simple. In other words, in comparison with the embodiment of FIG. 7, since the electrode 1 and the magnetic circuit 5 are placed in the atmosphere, materials whose manufacturing method and the like should not be used in a vacuum can be used. Also, when cooling is necessary to discharge by high power microwave,
Both the electrode 1 and the magnetic circuit 5 can be easily forcibly air-cooled, and the design of a water-cooled structure is also easy. The insulator 29 is not required which also serves as a vacuum seal in the coaxial line 6, it is possible to realize simplification and improvement of the reliability of the structure. Another advantage is that since the electrode 1 does not come into direct contact with the discharge plasma, it is possible to avoid contamination of the substrate 24 to be processed due to sputtering of the electrode 1 and adhesion of dirt to the inside of the vacuum vessel 30 due to sputtering of the electrode 1. Can be. Due to the above advantages, this embodiment has preferable characteristics as a microwave discharge reaction device.

FIG. 9 shows still another embodiment of the microwave discharge reactor. In the present embodiment, in the configuration of the embodiment shown in FIG. 8, the window 31 is provided on the atmosphere side with respect to the electrode 1, and vacuum sealing is performed using two O-rings 41 and 42. The shape of the shield plate 33 located on the atmosphere side of the window 31 and the magnetic circuit 5 disposed outside the shield plate 33 are the same as those in the above embodiment. The electrode 1 and the upper edge flange of the vacuum vessel 40 are insulated by a ring-shaped insulator 43, and are simultaneously vacuum-sealed by O-rings 44 and 45. In this configuration, the electrode 1 comes into contact with the plasma. However, if mixing of impurities into the substrate 24 to be processed by the
It is effective to cover the vacuum side surface with a thin insulator that does not become a source of contamination.

Another magnetic circuit 46 is provided outside the vacuum vessel 40.
Is installed. The magnetic circuit 46 includes a large number of permanent magnets 31 of which only a part is shown in FIG. 9, and a yoke (not shown) may be used if necessary. Each permanent magnet of the magnetic circuit 46
Usually, good results have been obtained when adjacent magnets are arranged so that they have magnetic fields in opposite directions. The area where the magnetic circuit 46 is provided outside the vacuum vessel 40 is desirably on the entire surface in view of the effect of retaining plasma.
The back side of the substrate holder 21 should be avoided in order to improve the uniformity of the processing of step 4. The weaker magnetic field on the surface of the substrate 24 is advantageous for improving the processing uniformity.

The other structure is the same as that of the embodiment shown in FIG. However, in this example,
The substrate holder 21 is arranged close to the bottom wall of the vacuum vessel 40, and an insulator 23 extending between the substrate holder 21 and the bottom wall is arranged.

The operation of this embodiment is basically the same as the embodiment described with reference to FIG. As an advantage of this embodiment, the loss of plasma on the inner wall of the vacuum vessel 40 is reduced by the operation of the magnetic circuit 30, and it is easy to increase the density of plasma.
Accordingly, the processing speed of the substrate 24 can be increased.

[0051]

As is apparent from the above description, according to the present invention, a flat electrode having a slit having a predetermined shape and a length of the slit with respect to the electrode are provided in a vacuum vessel as a discharge reaction chamber. An electrode device consisting of a magnetic circuit that generates a magnetic field in the same direction as that of the electrode is disposed, microwaves are supplied to the electrode through a coaxial transmission line, the processing gas is turned into plasma, and the electric field generated by the electrode and the magnetic circuit cross each other. The plasma is generated in a very narrow area near the electrode surface under predetermined conditions by the action, so the microwave utilization efficiency is high,
A microwave plasma processing apparatus having good processing uniformity can be realized. In addition, it can be manufactured small and inexpensively with a simple configuration, can generate plasma with good uniformity, has good generation efficiency, and can perform uniform processing on a substrate having a large area. , Is highly practical.

[Brief description of the drawings]

FIG. 1 is a plan view showing a first embodiment of an electrode device.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a view similar to FIG. 1 for another embodiment of the electrode device.

FIG. 4 is a sectional view of a main part showing another embodiment of the electrode device.

FIG. 5 is a main part plan view for explaining a plasma generation mechanism in the electrode device according to the present invention.

FIG. 6 is a cross-sectional view of a main part for describing the plasma generation mechanism of FIG.

FIG. 7 is a longitudinal sectional view showing a first embodiment of the microwave discharge reaction device according to the present invention.

FIG. 8 is a longitudinal sectional view showing another embodiment of the microwave discharge reaction device according to the present invention.

FIG. 9 is a longitudinal sectional view showing another embodiment of the microwave discharge reaction device according to the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 flat electrode 2 slit 3 external electrode 4 internal electrode 5 magnetic circuit (magnetic field generating mechanism) 6 coaxial line (coaxial transmission line) 7 conductive flat plate 10 slit 11 flat electrode 14 slit 15 state of magnetic field 16 state of electric field 17 High-density plasma 20 Vacuum container 21 Substrate holder 22 Reaction gas introduction mechanism 26 Exhaust system 28 Microwave power supply mechanism

Continuation of the front page (51) Int.Cl. ⁶ Identification code FI H01L 21/31 H01L 21/31 C (72) Inventor Tetsu Iizuka 6-10-10-201, Koriyama, Taishiro-ku, Sendai City, Miyagi Prefecture (72) Inventor Yukito Nakagawa 5-8-1, Yotsuya, Fuchu-shi, Tokyo Nidec Anelva Co., Ltd. (56) References JP-A-3-215659 (JP, A) JP-A-1-258400 (JP, A) JP-A-1- 184922 (JP, A) JP-A-2-288228 (JP, A) JP-A-1-187824 (JP, A) JP-A-63-228549 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H05H 1/46 C23C 16/50 C23F 4/00 H01L 21/3065

Claims (7)

(57) [Claims] 1. A vacuum vessel having a mechanism for maintaining the interior in a reduced pressure state and a mechanism for introducing a gas, a plasma generating mechanism for introducing a microwave into the vacuum vessel to convert the gas into plasma, In a microwave discharge reaction device including a generation mechanism and a substrate holding mechanism provided at an interval, the plasma generation mechanism includes a coaxial transmission line that introduces the microwave into the vacuum vessel, and a microwave. a flat electrode at least 1 inborn slits of a predetermined length and width for radiating waves, disposed in the vicinity of the flat plate-shaped electrode, discharge radially in said slit
A magnetic field generating means for generating a magnetic field closed in the same direction as the length direction of the projecting portion , a microwave radiated into a vacuum vessel by the electrode, and an electric field of the microwave by the magnetic field generating means. microwave discharge reaction device characterized by the interaction of the orthogonal magnetic field generated in the direction of generating a plasma in front space of the substrate holding device. 2. The microwave discharge reaction device according to claim 1, wherein the radius of the slit formed in the electrode is smaller than the radius of the slit formed in the electrode.
The directional radial portion is arranged radially from the center of the electrode, and the magnetic field generating means is on a concentric circle sharing the center with the electrode, and the direction of the magnetic field is perpendicular to the electrode on the electrode surface. A microwave discharge reaction device comprising a plurality of cylindrical permanent magnets arranged. 3. The microwave discharge reaction apparatus according to claim 1, wherein a target for performing dielectric sputtering is set on a surface of the plasma generation mechanism where plasma is generated. Wave discharge reactor. 4. The microwave discharge reactor according to claim 1, further comprising a mechanism for moving at least one of the substrate to be processed and the magnetic field generating means. Microwave discharge reactor. 5. A plate-shaped electrode to which a microwave is supplied and which has at least one slit having a predetermined length and width for radiating the microwave, and a direction in the same direction as the length direction of the slit in the vicinity of the electrode. An electrode device comprising: a magnetic field generating means arranged to generate a magnetic field. 6. The electrode device according to claim 5, wherein the slit is arranged radially from a center of the electrode, and the magnetic field generating means is on a concentric circle sharing a center with the electrode, An electrode device comprising a plurality of cylindrical permanent magnets arranged so that directions are perpendicular to the electrodes on the electrode surface. 7. The electrode device according to claim 5, wherein the electrode comprises an external electrode and an internal electrode having the slit positioned therebetween.