JP3225283B2 - Surface treatment equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface treatment apparatus, and more particularly to a surface treatment apparatus for performing surface treatment of a substrate by using plasma generated by a discharge caused by direct current, high frequency, microwave, or the like. The present invention relates to a surface treatment device used as an etching device or a plasma CVD device.

[0002]

2. Description of the Related Art As an example of a conventional surface treatment apparatus, a high-frequency discharge reaction apparatus used in a dry etching step which is one of semiconductor device manufacturing steps will be described. In a wiring pattern forming process that is indispensable for semiconductor device fabrication, a dry etching technique is used. In dry etching technology, a gas mixture containing a gas containing halogen as a main component is turned into plasma by electric discharge, and various active species (eg, atomic chlorine, atomic fluorine, fluorine-carbon compound, etc.) generated by the plasma are converted into a thin film on the substrate surface. The reaction is carried out to remove unnecessary thin film portions as wiring. The most common method for converting a mixed gas into a plasma is to provide two flat electrodes in a vacuum vessel having a reduced pressure, supply high-frequency power to one electrode, and connect the other electrode to ground potential. In this method, a discharge is caused by the energy of the high-frequency power and plasma is generated between the two electrodes.
An apparatus using this method is called a parallel plate type discharge reaction apparatus and is used in a wide range of fields.

As an improved type of the parallel plate type discharge reactor, there is known a magnetron type discharge reactor in which the efficiency of plasma generation is increased by adding a magnetic field generating means for generating a magnetic field in a vacuum vessel.

FIG. 7 shows an example of a conventional typical configuration of a parallel plate type discharge reactor used in a dry etching apparatus.
This will be outlined. Reference numeral 71 denotes a vacuum vessel, 72 denotes an electrode for generating discharge serving also as a substrate holding mechanism, and 73 denotes an electrode 72.
The electrode 74 facing the substrate is a substrate to be processed. Electrode 7
3 is kept at the ground potential. 75 is an exhaust mechanism for bringing the inside of the vacuum vessel 71 into a required reduced pressure state, 76 is a vacuum vessel 71
This is a gas introduction pipe for supplying a reaction gas into the inside of the tube.
An RF power is supplied to the electrode 72, and an RF power supply 77 and a matching circuit 78 are additionally provided as a mechanism for that. Electrode 7
2 is provided with an insulator 79 also serving as a vacuum seal.

FIG. 8 shows a configuration of a conventional magnetron discharge reactor used as a dry etching apparatus. Many types of dry etching apparatuses using a magnetic field have been developed. Here, an example of a so-called rotating magnetic field type apparatus is shown. 8, the same elements as those shown in FIG. 7 are denoted by the same reference numerals. That is,
71 is a vacuum vessel, 72 is an electrode also serving as a substrate holding mechanism, 7
3 is a counter electrode, 74 is a substrate, 75 is an exhaust mechanism, 76 is a gas introduction tube, 77 is an RF power supply, 78 is a matching circuit, and 79 is an insulator. Further, an electromagnet device 80 having a ring shape around the outside of the vacuum vessel 71 and having a special magnetic pole arrangement structure is installed inside. According to the electromagnet device 80 having this special magnetic pole arrangement structure, the magnetic field vector (magnetic flux density B) is set in a direction parallel to the surface of the substrate 74 to be processed.
81 (Reference: Journal of Nuc
lear Materials 200 (1993) pp291-295). It is also common to rotate the direction of the magnetic field vector 81 on the processing surface of the substrate 74.

Conventionally, each of the above two types of discharge reaction apparatuses has been widely used as a dry etching apparatus for etching the surface of a substrate to be processed, and has a line width of 1 μm.
It has a sufficient performance with respect to etching for fine processing of about m, and has been used in many semiconductor factories.

[0007]

The above-mentioned conventional dry etching apparatus has the following problems.

The most important reason for utilizing dry etching in microfabrication in a semiconductor device manufacturing process is that anisotropic etching, that is, etching having a vertical cross section, is possible. However, in order to obtain a vertical cross section of a fine structure of 1 μm or less by dry etching, ions in the plasma must be perpendicularly incident on the substrate to be processed. The simplest method for improving the straightness of the ions is to lower the discharge pressure.

However, in the parallel plate type discharge reactor shown in FIG. 7, if the discharge pressure is too low, the plasma density decreases, and a sufficient processing speed cannot be obtained. If the discharge pressure is reduced, the discharge itself cannot be maintained. Therefore,
There is a limit to reducing the discharge pressure. Further, by lowering the discharge pressure, the self-bias voltage on the cathode (electrode 74) becomes large, whereby the ion incident energy on the substrate 74 becomes too large, and there is a danger that the surface of the substrate is damaged. Increase.

From the viewpoint of reducing the incident energy of plasma ions and preventing damage to the substrate surface, application of the magnetron discharge reactor shown in FIG. 8 has been widely attempted. In the magnetron type discharge reactor, the plasma is generated by using an external magnetic field in combination, so that the discharge voltage can be reduced (1 to 10 mTorr) without increasing the self-bias voltage on the cathode, and as a result, The irradiation energy of ions to the substrate can be reduced. In addition, there is an advantage that discharge can be performed even at a lower discharge pressure as compared with a parallel plate type discharge reactor.

However, the magnetron discharge reactor has a problem in that the generated plasma is unevenly distributed depending on the distribution state of the generated magnetic field, and thus the uniformity of the plasma is poor.

In view of the above problems, an object of the present invention is to provide a surface treatment apparatus which has a simple structure, can generate plasma at a low pressure, and can reduce the irradiation energy of ions on a substrate to be processed. Is to provide.

[0012]

According to the present invention, there is provided a surface treatment apparatus comprising: a vacuum vessel having a peripheral portion; an exhaust mechanism for reducing the pressure in the vacuum vessel; and a gas for introducing a discharge gas into the vacuum vessel. and introducing mechanism, a discharge electrode of the tubular for generating plasma discharges the gas, the power supply mechanism for supplying electric power for plasma generation to the discharge electrode, a magnetic circuit which is installed around the discharge electrode If, comprising at least one substrate holding mechanism are placed in a vacuum vessel, the tubular discharge collector
The poles are supplied with high-frequency power from the power supply mechanism and
Is maintained at ground potential and used as the other electrode.
The cylindrical discharge electrode and the peripheral surface of the vacuum vessel are coaxial.
The electrodes for cylindrical discharge are arranged in a vacuum vessel
Of the same size as the diameter of the peripheral surface of
Or smaller than the diameter of the peripheral surface of the vacuum vessel.
The magnetic circuit has a small diameter and is installed inside the peripheral surface, and the magnetic circuit is composed of a plurality of ring-shaped permanent magnets arranged coaxially and spaced apart from the discharge electrode and the peripheral surface of the vacuum vessel . The ring-shaped permanent magnets are radially magnetized so that the polarities of adjacent magnetic poles are opposite to each other, and at least two adjacent permanent magnets of the plurality of ring-shaped permanent magnets are arranged around the discharge electrode, In addition, other permanent magnets are arranged around the peripheral surface of the vacuum vessel corresponding to the front space of the substrate support mechanism, and a ring-shaped permanent magnet is arranged around the discharge electrode.
Huge magnet inside the discharge electrode and along the inner surface of the discharge electrode
To generate plasma by confining plasma electrons
Generated on the peripheral surface of the vacuum vessel
Charged particles in the plasma along the peripheral surface of the ring-shaped permanent magnet
The surface of the substrate holding mechanism on which the substrate to be processed is generated is arranged perpendicular to the center axis of the discharge electrode near the end of the magnetic circuit, for generating lines of magnetic force for preventing collision of the inner wall surface of the child .

[0013] In the above configuration, preferably, the discharge electrode is provided with a phosphor between both sides thereof and a peripheral surface of the vacuum vessel.
While maintaining the vacuum seal by interposed a grayed-like insulator is provided as a part of the peripheral surface of the vacuum vessel, on both sides of the peripheral surface
Each part is grounded .

In each of the above structures, preferably, the discharge electrode is coaxially arranged inside the vacuum vessel with a gap between the discharge electrode and the peripheral surface of the vacuum vessel, and both ends are provided. It has a opened tubular shape, circumference of the discharge electrode
The ring-shaped permanent magnet placed in the surrounding area
It is located outside.

In the above configuration, preferably, another cylindrical electrode surrounding the discharge electrode is coaxially arranged between the vacuum vessel and the discharge electrode, and the length of the cylindrical electrode in the axial direction is preferably smaller than that of the discharge electrode. It is longer than the axial length of the electrode, the cylindrical electrode is held at a floating potential, and each ring-shaped permanent magnet of the magnetic circuit is
It is arranged around the cylindrical electrode instead of around the peripheral surface of the vacuum vessel . Note that the cylindrical electrode may be provided with a structure to which a bias voltage can be applied instead of holding the floating electrode.

In the above configuration, preferably, the ring-shaped permanent magnet disposed at a position corresponding to the periphery of the discharge electrode is disposed by utilizing a space between the discharge electrode and the cylindrical electrode.

In the above configuration, preferably, the discharge electrode is formed of a cylindrical member composed of two portions having the same axial length and different diameters, and is configured using two or more ring-shaped permanent magnets. Another magnetic circuit is arranged around a small diameter portion of the discharge electrode.

In the above configuration, preferably, the discharge electrode is formed in a bellows shape by alternately arranging the portions having different diameters.

In the above configuration, the discharge electrode has an inner / outer dual structure including an internal electrode and an external electrode, and a ring-shaped permanent magnet is disposed between the internal electrode and the external electrode.

In the above configuration, a sufficient gap for generating a discharge is formed between the external electrode and the cylindrical electrode.

In the above configuration, the magnetic poles at the opposite portions of the ring-shaped permanent magnet disposed on the discharge electrode and the ring-shaped permanent magnet disposed at a position corresponding to the discharge electrode in the cylindrical electrode have the same polarity. is there.

[0022]

According to the present invention, a surface treatment apparatus capable of generating high-density plasma with good uniformity at low pressure is proposed. By utilizing a magnetic field conventionally used for confining plasma for plasma generation at the same time. And high-density plasma with good uniformity can be easily generated. Further, as a configuration for simultaneously utilizing the lines of magnetic force for generating and confining plasma, it is desirable to apply a high-frequency discharge mechanism.

In the surface treatment apparatus, the structure of an electrode for supplying high-frequency power for generating a discharge for generating plasma is changed from a conventional flat plate to a cylindrical one, and a ring-shaped electrode is formed around the outer periphery of the discharge electrode. A permanent magnet is arranged. As a result, plasma is generated inside the cylindrical discharge electrode and diffuses inside the vacuum vessel. Further, the density of the plasma is increased by the magnetic field generated by the ring-shaped permanent magnet as compared with the related art. Further, the high-density plasma diffuses into the vacuum vessel and is uniformly confined in the space inside the vacuum vessel by the lines of magnetic force of the ring-shaped permanent magnets arranged outside the discharge space.

As described above, the lines of magnetic force used for confining the plasma are also used for the generation of the plasma, thereby efficiently generating a high-density plasma at a low pressure and improving the uniformity of the plasma.

[0025]

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

FIG. 1 is a longitudinal sectional view showing the structure of a first embodiment of the surface treatment apparatus according to the present invention. In FIG. 1, reference numeral 1 denotes a vacuum vessel as a whole, and a cylindrical (for example, cylindrical) discharge electrode 2 is provided at the center of the vacuum vessel 1. The discharge electrode 2 is made up of two ring-shaped insulators 3 arranged on both sides thereof, and is formed on both sides (made of metal) 1A,
1B. The vacuum container 1 is formed as a hermetically sealed container by the cylindrical discharge electrode 2 and both side portions 1A and 1B, and the portion excluding the end surfaces 1a and 1b has a cylindrical shape such as a cylinder. . The portion having this cylindrical shape is referred to herein as a “peripheral surface portion”. The ring-shaped insulator 3 is provided on both sides 1A and 1A of the vacuum vessel 1.
It has a structure for vacuum sealing between each of the electrodes B and the discharge electrode 2. The internal space of the vacuum vessel 1 is maintained in a required vacuum state (decompressed state) when performing the surface treatment, and discharges the introduced discharge gas to generate a necessary plasma. Both sides 1A and 1B of the vacuum vessel 1 are kept at the ground potential.

In the vacuum vessel 1, for example, two substrate holding mechanisms 5 are installed with their substrate holding surfaces facing each other. The substrate holding mechanism 5 is attached to the end surfaces 1a and 1b on both sides of the vacuum vessel 1. Surface treatment is performed on the substrate to be processed 6 mounted on each of the two substrate holding mechanisms 5.

A magnetic circuit 4 composed of a ring-shaped permanent magnet is installed around the outer periphery of the cylindrical peripheral surface including the discharge electrode 2 in the vacuum vessel 1. The magnetic circuit 4 includes a plurality of ring-shaped permanent magnets 401 and 40 arranged at appropriate intervals.
It consists of two. The ring-shaped permanent magnets 401 and 402
It is arranged at a coaxial position with respect to the peripheral surface portion including the discharge electrode 2. At least two permanent magnets 401 are arranged around both sides 1A, 1B of the vacuum vessel 1, and at least two permanent magnets 402 are arranged around the discharge electrode 2.
Both sides 1A and 1B of the vacuum vessel 1 each have a front space of the substrate 6 of each substrate holding mechanism 5 therein, and the ring-shaped permanent magnet 401 is installed so as to surround the front space.
In the configuration of the magnetic circuit 4 including the plurality of permanent magnets 401 and 402, as shown in FIG. 1, the ring-shaped permanent magnets are magnetized in the radial direction, and the arrangement of the magnetic poles is reversed between adjacent permanent magnets. It is magnetized.

The surface of the substrate holding mechanism 5 on which the substrate to be processed 6 is placed is disposed near the end of the magnetic circuit 4 and perpendicular to the center axis of the discharge electrode 2.

An exhaust mechanism 7 is provided on the end surface 1a of the vacuum vessel 1 to exhaust gas existing in its internal space. A predetermined flow rate of a predetermined gas is introduced into the vacuum vessel 1 by a gas introduction pipe 8 and a gas introduction mechanism (not shown). The pressure in the vacuum vessel 1 can be set to a predetermined value by adjusting the exhaust speed of the exhaust mechanism 7 and the gas introduction flow rate by the gas introduction mechanism.

A power supply mechanism is attached to the discharge electrode 2 to supply necessary power. The power supply mechanism includes a high-frequency (RF) power supply 10 and a matching circuit 11, and supplies the high-frequency power generated by the high-frequency power supply 10 to the matching circuit 11.
And supply it to the electrode 2 via the feed line 12.

The power supply mechanism is understood in a broad sense,
It includes a high-frequency and microwave power supply mechanism. However, in this embodiment, an application example of 13.56 MHz specified as a high frequency, particularly an industrial frequency will be described.

With reference to FIGS. 1 and 2, the basic operation of the surface treatment apparatus based on the above configuration will be described. FIG. 2 is a diagram showing the shape of the magnetic field by the magnetic circuit 4 and the state of plasma generation due to the influence thereof. In this figure, the vacuum vessel 1 is shown in a simplified manner, and the insulator 3 and the substrate holding mechanism 5 are omitted. .

First, the inside of the vacuum vessel 1 is evacuated by the exhaust mechanism 7 to a required reduced pressure state. Thereafter, a predetermined gas is introduced into the vacuum vessel 1 by the gas introduction pipe 6 and the gas introduction mechanism so as to have a predetermined pressure. I do. This predetermined pressure is
The optimum values are set according to the gas type, the magnetic field strength, and the like.

Next, the high-frequency power generated by the high-frequency power supply 10 is supplied to the discharge electrode 2 through the matching circuit 11. As a result, high-frequency discharge is generated in the space inside the cylindrical discharge electrode 2, and plasma is generated. The state of plasma generation at this time is determined depending on the configuration of the magnetic circuit 4.

As shown in FIGS. 1 and 2, in this embodiment, the ring-shaped permanent magnets constituting the magnetic circuit 4 are divided into two groups (a permanent magnet 401 and a permanent magnet 402) according to their operation characteristics. Provided. The effect of the permanent magnet 401 is that the lines of magnetic force 501 generated by the permanent magnet 401 cross only the container walls of both sides 1A and 1B of the vacuum container 1. The action of the permanent magnet 402 is
2 is that the magnetic field line 502 formed by the second electrode 2 crosses the discharge electrode 2 and spreads in its internal space. Permanent magnet 401
And the magnetic field lines 503 generated at the boundary of the permanent magnet 402
Crosses both the vessel walls of both sides 1A and 1B of the vacuum vessel 1 and the discharge electrode 2.

In the surface treatment vacuum vessel 1 provided with the magnetic circuit 4 that produces the above-mentioned action, the plasma generated in the internal space using the discharge electrode 2 has the following characteristics. When high-frequency power is supplied to the discharge electrode 2 to generate plasma, an electric field (an electric field as an average value) due to a high-frequency voltage exists on the surface of the electrode 2, and electrons accelerated by the electric field are generated in the vacuum vessel 1. By colliding with the gas molecules (atoms) introduced into the gas and ionizing the gas molecules, particularly high-density plasma is locally generated and is diffused and maintained in the vacuum vessel 1. When plasma is generated,
The motion of the electrons in the plasma is determined by the magnetic field created by the magnetic circuit 4. In the present embodiment, a particularly high-density plasma 505 is generated at the location shown in FIG. 2 based on the interaction with the magnetic field 502. The mechanism for generating and maintaining plasma in this embodiment is basically the same as that of a conventional magnetron discharge reactor. However, to describe in more detail, the plasma generation / maintenance mechanism of the present embodiment has the following features due to the configuration of the discharge electrode 2 for plasma generation and the ring-shaped permanent magnet 402 installed around the electrode 2. .

There is a voltage drop (potential difference) between the inner surface of the cylindrical discharge electrode 2 and the plasma generated in the internal space, and a DC electric field (electrostatic field) exists therein. The direction of movement of the electrons in the plasma is determined by this electric field and the component of the magnetic field 502 generated by the permanent magnet 402 that is orthogonal to the electric field. Specifically, the electrons move in the direction of the outer product of the electric field vector and the magnetic field vector (inward in the radial direction), and move in the circumferential direction along the inner wall of the discharge electrode 2 based on the action of the electric field and the magnetic field. , Its movement path is closed. By closing the movement path of the electrons in the plasma generation region as described above, the dissipation of the electrons in the plasma generation region is suppressed, and the local high-density plasma can be easily generated and maintained. The feature of the high-density plasma generated by the configuration of the present embodiment is that, as shown by 505 in FIG. 2, a ring-shaped region is formed close to the inner surface of the discharge electrode 2 and the high-density plasma is Is to be generated. In order to generate plasma in the ring-shaped region, as described above, a plurality of ring-shaped permanent magnets 402 are alternately arranged around the cylindrical discharge electrode 2 with the magnetic poles arranged alternately, and the magnetic force lines formed by these are arranged. It is necessary that 502 crosses and crosses the inner surface of the discharge electrode 2.

In the plasma generated in the space inside the discharge electrode 2 as described above, ions and activated gas molecules or atoms existing therein are removed from the vacuum vessel 1.
, And reacts with the thin film formed on the surface of the substrate 6 to be removed. At this time, the permanent magnet 4
01 reduces the loss of charged particles in the plasma due to collision with the inner wall surfaces of both sides 1A and 1B of the vacuum vessel 1, keeps the density of the plasma high, and the vicinity of the surface of the substrate 6 to be processed. Has the function of improving the uniformity of the plasma density at

In the above embodiment, both sides 1 of the vacuum vessel are used.
Since the vacuum vessel 1 is formed by integrating the electrodes A and 1B and the discharge electrode 2, it is not necessary to dispose the discharge electrode in the vacuum vessel 1. Further, since the magnetic circuit 4 can be installed in the atmosphere, it is easy to provide a structure for cooling the magnetic circuit 4 and has structural advantages such as easy maintenance and management.

As is apparent from the above embodiment, the feature of the present invention is that a high-density plasma 505 existing in a ring-shaped region is generated by using a magnetic field 502, and ions and activity generated by the high-density plasma 505 are generated. The gas molecules or atoms that have been converted are efficiently and uniformly diffused by another magnetic field 501, thereby enabling the surface treatment of the substrate 6 to be processed.

Next, a second embodiment of the present invention will be described with reference to FIG. In FIG. 2, substantially the same elements as those described in FIG. 1 are denoted by the same reference numerals. The feature of the present embodiment is that a discharge electrode is prepared separately from the vacuum vessel, and this cylindrical discharge electrode is provided inside the vacuum vessel 1,
It is located at the coaxial position and at the axial center position. Reference numeral 2 denotes a cylindrical discharge electrode, which is made smaller in diameter than the vacuum vessel 1. Illustration of the member supporting the electrode 2 is omitted. The discharge electrode 2 is supplied with high-frequency power by a power supply line 12 wired through a small pipe-shaped insulator 13 also serving as a vacuum sealing member, and generates plasma with the high-frequency power. The gap 14 between the vacuum vessel 1 and the discharge electrode 2 needs to be small enough to prevent discharge from entering between them. The size of this interval varies depending on the type and pressure of the gas to be discharged, but is generally desirably about several millimeters (mm). Further, the vacuum vessel 1 is maintained at the ground potential.

In this embodiment, the structure of the ring-shaped insulator 3 and the connection between the electrode 2 and both sides 1A and 1B of the vacuum vessel, which is required in the first embodiment, becomes unnecessary. This has the advantage that the configuration is simplified. Further, since the discharge electrode 2 and the vacuum vessel 1 are made as separate members, the vacuum vessel 1 having a large peripheral surface portion can be easily made. Other device configuration and permanent magnet 40
The magnetization directions of 1,402 are exactly the same as in the first embodiment. Also in this embodiment, the mechanism for generating and maintaining the plasma is exactly the same as that described in the first embodiment.

In the first and second embodiments described above, the inner surface of the vacuum vessel 1 has a characteristic that it is easily sputtered by ions in the plasma. In particular, when applying a DC or AC bias to the substrate holding mechanism 5 to process the surface of the substrate 6 to be processed, problems such as spattering of the inner wall of the vacuum vessel 1 and unstable discharge occur. This is because in each of the above-described embodiments, a vacuum vessel at a ground potential is used as an electrode. That is, the plasma potential changes in accordance with the bias of the substrate holding mechanism 5, and the potential difference between the plasma potential and the ground potential, that is, the DC electric field in the sheath formed on the inner wall surface of the vacuum vessel 1 increases, thereby accelerating ions. This is because the resulting sputtering is likely to occur. Further, when the potential difference becomes extremely large, a local arc discharge occurs,
The state of the plasma may become unstable. In order to solve such a problem, the following embodiment is proposed.

A third embodiment of the present invention will be described with reference to FIG. The feature of this embodiment is that a second cylindrical electrode 9 (hereinafter referred to as a cylindrical electrode 9) is provided between the discharge electrode 2 and the vacuum vessel 1 in the configuration of the second embodiment. It is in. The cylindrical electrode 9 is an anode, and is formed such that its axial length is longer than that of the discharge electrode 2. Further, preferably, the cylindrical electrode 9 is fixed to the vacuum vessel 1 via an insulator (not shown) and is electrically floated. If necessary, a bias application structure including a bias power supply 19 may be provided on the cylindrical electrode 9, and an arbitrary bias (including a ground potential) may be applied by the bias power supply 19. The magnetic circuit 4 is provided between the voltage cylindrical electrode 9 and the vacuum vessel 1. The structure of the magnetic circuit 4 is the same as in the first and second embodiments.

The discharge electrode 2 is wired through an insulator 13 similar to that of the second embodiment and a small similar insulator 16 serving also as a vacuum sealing member provided on the cylindrical electrode 9. High-frequency power is supplied by the electric wire 12, and plasma is generated by the high-frequency power. The insulator 16 can also be provided as the same thing by extending the insulator 13. The mechanism for generating and maintaining plasma in this embodiment is the same as the mechanism described in each of the above embodiments. The gap 15 between the discharge electrode 2 and the cylindrical electrode 9 is so small that the discharge does not enter between them, and is almost the same in dimension as the gap 14. In addition, a gap is formed between the cylindrical electrode 9 and the vacuum vessel 1 that is sufficient for the magnetic circuit 4 to be installed. If there is not enough space to provide the magnetic circuit 4 between the vacuum vessel 1 and the cylindrical electrode 9, the magnetic circuit 4
Can be installed outside the vacuum vessel 1.

According to the third embodiment, the electric potential of the cylindrical electrode 9 is maintained even when a DC or AC bias is applied to the substrate holding mechanism 5 by electrically floating the cylindrical electrode 9. Since the potential changes according to the plasma potential, the potential difference from the plasma potential is kept small, and the problem in the second embodiment is eliminated. If the substrate holding mechanism 5 is difficult to apply a bias voltage due to its structure,
By applying a bias to the cylindrical electrode 9, the energy of ions incident on the substrate 6 to be processed can be controlled. Further, in the discharge at a high frequency, the spatial potential of the plasma in the vicinity of the processing target substrate 6 oscillates by the high frequency, and the energy width of ions incident on the processing target substrate 6 is widened, which may adversely affect the fine processing process. In this case, the third
Instead of the bias power supply in the figure, the vacuum vessel 1 and the cylindrical electrode 9 are connected via a capacitor, thereby eliminating high-frequency vibration of the potential of the cylindrical electrode 9 and suppressing vibration of the plasma spatial potential. it can. The capacity of the capacitor may be any that has a sufficiently low impedance with respect to the high frequency of the frequency used for discharging.

Next, a fourth embodiment of the present invention will be described with reference to FIG. In the present embodiment, in the configuration of the third embodiment described above, a large-diameter portion (large-diameter portion) 201 and a small-diameter portion (small-diameter portion) 202 are provided alternately and continuously in the discharge electrode 2. It has a structure. Discharge electrode 2
Has a shape similar to a bellows shape in which a small diameter portion and a large diameter portion are repeatedly formed in the axial direction. A permanent magnet 402 for generating plasma in the magnetic circuit 4 is provided in a space between the small-diameter portion 202 of the discharge electrode 2 and the cylindrical electrode 9. The gap 17 between the large-diameter portion 201 of the discharge electrode 2 and the cylindrical electrode 9 needs to be small enough to prevent discharge from entering between them.
It is almost the same as 4. It is desirable to provide a similar gap between the permanent magnet 402 and the cylindrical electrode 9. However, when the material of the permanent magnet 402 is an insulator such as ferrite, the gap is not necessarily required. The other device configuration and the magnetization direction of the permanent magnet are exactly the same as those in the third embodiment.

The plasma is generated in the space inside the large-diameter portion 201 of the discharge electrode 2. In the plasma generation according to the present embodiment, the high-density plasma is generated and maintained by the magnetron discharge described in the first embodiment, and the so-called hollow cathode effect (electrons reciprocate between cathodes installed in close proximity). By using a plasma generation / maintenance mechanism based on the action of generating high-density plasma, plasma density can be further increased.

A fifth embodiment of the present invention will be described with reference to FIG. The feature of this embodiment lies in the structure of the cylindrical permanent magnet 402 constituting the discharge electrode 2 and the magnetic circuit for plasma generation. In this embodiment, the discharge electrode 2 has a portion 203 having the same axial length and a small diameter (hereinafter referred to as an internal electrode) and a portion having a large diameter (hereinafter referred to as an external electrode) 204.
Are arranged inside and outside of each other and electrically connected. The gap 18 between the external electrode 204 and the discharge electrode 2 had to be small enough to prevent discharge from entering between them in each of the above-described embodiments. In order to use it as a working space, it is formed as a large gap to some extent. The size of the gap 18 varies depending on the pressure of the gas to be discharged, but is generally desirably about several centimeters (cm).

Further, two or more ring-shaped permanent magnets 403 for generating plasma are arranged in a space between the internal electrode 203 and the external electrode 204 of the discharge electrode 2. The magnetization direction of the ring-shaped permanent magnet 403 is performed in the same manner as in the case of the permanent magnet 401. Further, the position of the permanent magnet 403 is arranged such that its outer magnetic pole faces the inner magnetic pole of the ring-shaped permanent magnet 402, and the direction of the magnetic pole is such that the magnetic poles of the ring-shaped permanent magnet 402 and the ring-shaped permanent magnet 403 face each other. Install so that they have the same pole. The other device configurations and the magnetization directions of the other permanent magnets 401 and 402 are exactly the same as in the first embodiment.

The cylindrical electrode 9 has a floating potential also in this embodiment, and the basic operation principle of the electrode 9 is the same as that of the fourth embodiment.

In this embodiment, the plasma is generated in two places: a space inside the internal electrode 203 of the discharge electrode 2 and a gap 18 between the external electrode 204 of the discharge electrode 2 and the cylindrical electrode 9. . The mechanism for generating and maintaining plasma generated in the space inside the internal electrode 203 is exactly the same as the mechanism described in the first embodiment. Gap 1
Regarding the generation of plasma in FIG. 8, the plasma generation / maintenance mechanism using the magnetron discharge and the hollow cathode effect described in the second embodiment has a structure capable of realizing a higher density of plasma.

In each of the above embodiments, two substrate holding mechanisms are provided in a symmetrical positional relationship in the vacuum vessel. However, only one substrate holding mechanism may be provided.

[0055]

As is apparent from the above description, according to the present invention, in a surface treatment apparatus using a magnetron discharge utilizing a high frequency or the like, a part of the lines of magnetic force conventionally used for preventing plasma loss is reduced by the magnetron discharge. Since the shape of the discharge electrode has been devised so that it can be used for plasma generation by, a high-density plasma can be generated efficiently and the uniformity of surface treatment can be maintained on the substrate to be processed. The present invention is a dry etching apparatus that is a plasma processing apparatus that requires various high-speed and uniform large-area processing,
When applied to a CVD apparatus or the like, the effect becomes remarkable.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a configuration of a first embodiment of a surface treatment apparatus according to the present invention.

FIG. 2 is a diagram showing a main part in FIG. 1;

FIG. 3 is a longitudinal sectional view showing a second embodiment of the present invention.

FIG. 4 is a longitudinal sectional view showing a third embodiment of the present invention.

FIG. 5 is a longitudinal sectional view showing a fourth embodiment of the present invention.

FIG. 6 is a longitudinal sectional view showing a fifth embodiment of the present invention.

FIG. 7 is a sectional view showing an example of a conventional parallel plate type surface treatment apparatus.

FIG. 8 is a sectional view showing an example of a conventional magnetron type surface treatment apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vacuum container 1A, 1B Both sides of a vacuum container 2 Discharge electrode 3 Insulator 4 Magnetic circuit 5 Substrate holding mechanism 6 Substrate to be processed 7 Evacuation mechanism 8 Gas introduction mechanism 401,402 Ring-shaped permanent magnet 501,502,502 Magnetic field (magnetic field lines) )

Continuation of front page (56) References JP-A-5-315096 (JP, A) JP-A-5-129094 (JP, A) JP-A-2-222532 (JP, A) JP-A-62-203328 (JP) , A) JP-A-62-147733 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 21/3065 C23C 16/509 C23F 4/00 H01L 21/205

Claims (10)

(57) [Claims] 1. A vacuum vessel made of metal having a peripheral surface portion, an exhaust mechanism for reducing the pressure in the vacuum vessel, a gas introduction mechanism for introducing a discharge gas into the vacuum vessel, and a plasma for discharging the gas. a cylindrical Katachiho conductive electrodes for generating,
A power supply for supplying power for plasma generation to this cylindrical discharge electrode
A power supply mechanism, a magnetic circuit provided around the cylindrical discharge electrode, and at least one magnetic circuit provided in the vacuum vessel.
In the surface treatment apparatus having two substrate holding mechanisms, the cylindrical discharge electrode is supplied with the high frequency power from the power supply mechanism.
And the vacuum vessel is held at ground potential and
The cylindrical discharge electrode and the peripheral surface of the vacuum vessel are the same.
An axially arranged positional relationship, and said cylindrical discharge electrode
Is a diameter of the same size as the diameter of the peripheral surface portion of the vacuum vessel
And used as a part of the peripheral surface, or
A diameter smaller than the diameter of the peripheral surface of the vacuum vessel,
The magnetic circuit is installed inside the peripheral portion, and the magnetic circuit is in front of the cylindrical discharge electrode and the vacuum vessel.
It is composed of a plurality of ring-shaped permanent magnets arranged coaxially and spaced apart from each other on the circumferential surface , and each of the ring-shaped permanent magnets is attached in the radial direction so that the polarities of adjacent magnetic poles are opposite to each other. At least two adjacent ring-shaped permanent magnets of the plurality of ring-shaped permanent magnets are magnetized.
Disposed around the cylindrical discharge electrode, and the other of the Li
Ring-shaped permanent magnets correspond to the front space of the substrate support mechanism.
The ring-shaped permanent magnet is disposed around the peripheral surface of the vacuum vessel, and is disposed around the cylindrical discharge electrode.
A magnet for the cylindrical discharge inside the cylindrical discharge electrode
The plasma electrons are confined along the inner surface of the
Generating magnetic field lines for generating plasma, the vacuum vessel
The ring-shaped permanent magnet arranged on the peripheral surface portion of the
Internal wall collision of charged particles in the plasma along the peripheral surface
Generate a line of magnetic force to prevent, the surface on which the substrate to be processed of the substrate holding mechanism is installed, is disposed perpendicular to the center axis of the cylindrical discharge electrode near the end of the magnetic circuit, A surface treatment apparatus characterized by the above-mentioned. 2. The surface treatment apparatus according to claim 1, wherein
The cylindrical discharge electrode, on both sides, of the vacuum vessel
Wherein provided as a part of the peripheral surface of the vacuum vessel while maintaining a vacuum seal by interposed a ring-shaped insulator between the peripheral surface, the peripheral surface of both sides grounded
Surface treatment apparatus characterized by being. 3. The surface treatment apparatus according to claim 1, wherein
The cylindrical discharge electrode is inside the vacuum container, the coaxially disposed with respect to the vacuum vessel with a gap between the peripheral surface of the vacuum container, and cylindrical with both ends open shape have a of, are disposed around the cylindrical discharge electrode
The ring-shaped permanent magnet is located outside the peripheral surface of the vacuum vessel.
A surface treatment apparatus, which is disposed on a side . 4. The surface treatment apparatus according to claim 3, wherein
The vacuum container and other tubular electrode surrounding said cylindrical discharge <br/> conductive electrode between the cylindrical discharge electrode is disposed coaxially,
The axial length of the cylindrical electrode is longer than the axial length of the cylindrical discharge electrode, the cylindrical electrode is held at a floating potential, and each ring-shaped permanent magnet of the magnetic circuit is
A surface treatment apparatus characterized by being arranged around the cylindrical electrode instead of around the peripheral surface of the vacuum vessel . 5. The surface treatment apparatus according to claim 4, wherein
Surface, characterized in that said ring-shaped permanent magnets arranged at a position corresponding to the periphery of the cylindrical discharge electrode was disposed by utilizing the space between the cylindrical electrode and the cylindrical discharge electrode Processing equipment. 6. A surface treatment apparatus according to claim 4 or 5, wherein, to form said cylindrical discharge electrode in cylindrical member consisting of two parts having different equal and diameters of the axial length, before
Surface treatment apparatus, wherein a further magnetic circuit constituting a serial ring-shaped permanent magnet with two or more arranged around the small portion of the diameter of the cylindrical discharge electrode. 7. The surface treatment apparatus according to claim 6, wherein
The surface treatment apparatus, wherein the cylindrical discharge electrode is formed in a bellows shape by alternately arranging the portions having different diameters. 8. The surface treatment apparatus according to claim 4 or 5, wherein the inner and outer double structure formed of the cylindrical discharge electrode from the internal electrodes and the external electrodes, the ring between the inner electrode and the outer electrode Surface treatment device characterized by disposing permanent magnets. 9. The surface treatment apparatus according to claim 8, wherein
A surface treatment apparatus, wherein a sufficient gap where discharge occurs is formed between the external electrode and the cylindrical electrode. 10. A surface treatment apparatus according to claim 8 or 9, wherein said ring-shaped permanent magnets arranged on the cylindrical discharge electrode, the portion corresponding to the cylindrical discharge electrode in the cylindrical electrode A surface treatment apparatus, wherein a magnetic pole at a portion facing the arranged ring-shaped permanent magnet has the same polarity.