JP2992193B2 - Compact electron beam excited plasma generator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The disclosed technology relates to a structure of an electron beam-excited ion irradiation apparatus for irradiating a target sample such as a silicon wafer with ions from plasma excited by an electron beam to perform a predetermined fine dry etching process or the like. Belongs to the technical field.

[0002]

2. Description of the Related Art As is well known, the remarkable prosperity of the industrial society has been strongly backed up by highly developed science, especially electronic engineering and quantum mechanics, and further development of such electronic engineering is strongly demanded. Have been.

[0003] Therefore, in the electronic engineering, when information processing of various data and the like is performed, it is more and more demanded that more sophisticated and precise processing be performed at an ultra-high speed. There is a strong demand for higher-tech, downsizing, etc. of devices that perform finer and more accurate ultra-high-speed arithmetic processing of such data. Processing techniques such as precise dry etching are required. To cope with this, for example, as disclosed in the invention of Japanese Patent Application Laid-Open No. 61-290629, an ion irradiation technique has been developed, so-called DC plasma, RF plasma. , ECR (electron cyclotron resonance) plasma,
Further, a system for exciting plasma by an electron beam or the like, accelerating ions in the plasma through an electric field, irradiating a target sample such as a silicon wafer, and performing fine processing such as dry etching has been researched and developed. It is being put to practical use.

However, in order to effectively perform fine dry etching or the like with good ions without leaving large damages due to ion irradiation in a recently enlarged target sample such as the silicon wafer. Irradiating the target sample with ions of uniform high current density over a large cross-sectional area in the low kinetic energy region is indispensable, and unless it is performed under such contradictory conditions. I've found that it doesn't.

[0005] However, in the case of an old type ion irradiation apparatus, if the current density of the ions in low kinetic energy ions is increased, it is difficult to uniformly irradiate the target sample with ions over a large cross-sectional area. there were.

To cope with this, for example, Japanese Patent Laid-Open No.
As disclosed in Japanese Patent No. 74960, a so-called electron beam excited plasma technique (EBEP) capable of generating high-density plasma capable of obtaining a large ion current density has been developed, and generation of an electron beam excited plasma as shown in FIG. The device 1 has been put into practical use, has various advantages in addition to the ECR (Electron Cyclotron Resonance) method, has been added to various development studies, and has been used in actual production.

That is, in the conventional electron beam excited ion irradiation apparatus 1 shown in FIGS. 12 and 13, the former electron beam gun 2 and the latter reaction chamber 3 are integrated,
In the cathode region 2 ', an argon gas 8 for forming an electron beam is supplied from a port 7, and the filament 5 of the cathode electrode 4 is heated by a DC power supply 6 to a red heat state to generate thermoelectrons. A voltage is applied between the discharge electrode 11 and the discharge electrode 11 having a hole 26 at the center of the latter stage by the discharge power source 10 to turn the argon gas 8 into plasma, and further, between the discharge electrode 11 and the later-stage acceleration electrode 13. Power supply 12
To accelerate the electrons extracted from the discharge region 14 in the electron beam acceleration region 15, drive the electrons into the reaction chamber 3 in the plasma region 3 ′, and supply the chlorine gas supplied from the port 18 of the reaction chamber 3. For example, the process gas 19 is turned into plasma, and the ions excited by the electron beam are transferred to the holder 2 in the reaction chamber 3.
A predetermined masked target sample 24 such as a silicon wafer supported by 3 is irradiated, and predetermined fine processing is performed by dry etching.

Reference numeral 25 denotes a probe, 21 denotes a multipole magnet, and 22 denotes a target sample of an electron beam.
This is a magnetic electromagnetic shutter provided to mitigate a straight collision.

Thus, in order to perform the fine dry etching of the target sample 24 having a large diameter in the reaction chamber 3 as designed and reliably, the amount of ions (the number of ions) is increased to increase the number of ions. Etching material target sample 24
A so-called selection ratio for improving the productivity by increasing the etching rate, reducing the ion velocity, reducing the processing amount for masking as much as possible, and reliably processing the target sample 24. It has been found that it is preferable to satisfy the contradictory conditions of decreasing the kinetic energy while increasing the ion current density in order to improve the ion current density.

By the way, the target sample 24 is
3 is in a so-called floating state in which the electron beam is electrically insulated. When the electron beam is incident on the floating region from the acceleration region 15, the electron beam is negatively charged.
Since the target sample 24 is irradiated with ions in the reaction chamber 3 through a potential difference (plasma potential-surface potential) formed on the surface to perform a desired dry etching process, the target sample 24 is covered by the masking described above. In order to increase the selectivity of the target sample 24 and to perform it as desired, it is necessary to suppress the potential difference in the state of being negatively charged by the electron beam in order to reduce the kinetic energy of ions. Until then, the following method was adopted.

That is, first, the acceleration voltage in the electron beam acceleration region 15, that is, the voltage between the acceleration electrode 13 and the discharge anode 11 is reduced, and the energy of the electron beam incident on the reaction chamber 3 is reduced. By reducing the negative charging voltage of the target sample 24, the target sample 2
4 is a method in which the potential difference formed on the surface of the target sample 4 is reduced to suppress the irradiation energy of ions. Second, a magnet 22 or the like is provided as a magnetic shutter immediately before the holder 23 of the target sample 24 so that the electron beam In this method, electrons entering the reaction chamber 3 from the acceleration region 15 are scattered so that high-energy electrons do not directly enter the target sample 24.

[0012]

However, in recent years, the advancement of higher technology in the industry has been promoted, and the diameter of the wafer or the like of the target sample 24 has been increased. As a result, the performance of the electron beam excited plasma generator 1 has been promoted. And, as compactness and downsizing of itself are desired, and further cost reduction is pursued,
The uniform early diffusion of the electron beam in the reaction chamber 3 is required, and therefore, as shown in FIG. A mode in which a reverse magnetic field coil 17 is provided on the outside and a multipole magnet 21 is provided on the inside has been adopted.

The magnetic field coils 16 and 16 ′ for controlling the electron beam are connected to the discharge electrode 11 and the acceleration electrode 13.
Means of arranging it outside were also taken.

The discharge electrode 11 is shown in FIG.
As shown in (1), one hole 26 for passing an electron beam is provided at the center of the hole 26 to accelerate the acceleration of the electron beam by the acceleration electrode 13.

As shown in FIG. 12, since the reverse magnetic field coil 17 is disposed outside the reaction chamber 3, its diameter must be increased.
Also, there is a problem that it is extremely difficult to accurately align the axis with the 16 '. As a result, the distribution of the magnetic field lines in the plasma region 3' becomes non-uniform, and the trajectory of the electron beam becomes non-axisymmetric. In addition, the rapid diffusion of the magnetic field lines is insufficient, and the electron beam cannot be spread sufficiently because it is emitted along the magnetic field lines, so that a uniform plasma cannot be formed. Since the diameter and length of the reaction chamber 3 need to be considerably large in order to promote the diffusion and promote the uniformity, there is a disadvantage that the apparatus cannot be made compact, and the ion current density decreases. In addition, there is a problem that non-uniformity must be caused.

Further, there is a disadvantage that energy loss due to heat generation at the time of generation of electrons and ions in the plasma region 3 'is increased, and in addition, the probe 25
Cooling pipe for the magnetic shutter 22 and the magnetic shutter 2
2 and multi-pole magnet 21 support the reaction chamber 3
However, there is a disadvantage that ions and electrons are lost on their surfaces due to the complicated arrangement, and the effect of hindering uniformity of the electron beam and good diffusion is unavoidable.

In the system using the magnetic shutter 22, the electron beam is applied to the magnetic shutter 22 and the multipole magnet 2
The amount of the electron beam passing through the bottleneck between the magnetic shutter 22 and the multi-pole magnet 21 is reduced because the beam passes through the bottleneck between the magnetic fields created by the magnetic poles 1 and 21 and reaches the front surface of the wafer of the target sample 24, so-called, This causes a decrease in the passage efficiency, a decrease in the plasma density on the front surface of the wafer of the target sample 24, and a problem that sufficient uniformity cannot be obtained.

In order to reduce the size of the apparatus in order to meet the needs of the research and industrial worlds, it is desirable to shorten the electron beam gun 2 on which the overall structure is based. The shorter the distance between the electrode 11 and the accelerating electrode 13 is, the smaller the scattering of the electron beam in the accelerating region 15 is, and the ratio of the electrons passing through the accelerating region 15 and being injected into the reaction chamber 3, that is, the passing efficiency is reduced. Although it is desirable to increase the height, if the capacity and diameter of the pump connected to the exhaust port 20 in the electron beam gun 2 are uniquely determined, the distance between the discharge electrode 11 and the acceleration electrode 13 is determined. Is determined, and as a result, there is a restriction that the electron beam gun 2 cannot be shortened.

To cope with this, Japanese Patent Laid-Open Publication No. 1-105553
9 and Japanese Patent Laid-Open No. 1-105540.
And Japanese Patent Application Laid-Open No. 1-176.
633, the invention described in JP-A-56-10
Although various inventions such as the invention disclosed in Japanese Patent Publication No. 2100 have been devised, none of the disclosed technologies can easily generate high-uniformity and high-density plasma, so that there is an obstacle to miniaturization of the apparatus. There was an insufficiency that it could not be solved fundamentally and that economical use of operating power could not be achieved.

[0020]

SUMMARY OF THE INVENTION It is an object of the invention of this application to provide, although potentially excellent advantages for the fine dry etching of a target sample such as a silicon wafer which is indispensable for the semiconductor technology based on the above-mentioned prior art, It is a technical task to solve various problems of the electron beam excited plasma generator that hinders uniform plasma generation and the downsizing of the apparatus, and the rapid diffusion of magnetic field lines in the reaction chamber. To achieve a highly uniform spread of the electron beam in the plasma chamber, high-precision emission of ions applied to the target sample, and a high degree of uniformity of the electron beam in the reaction chamber. Irradiation uniformity on the sample is significantly improved,
The target sample is placed in front of the wafer in the direction of the electron beam gun, and the reaction chamber in the plasma region can be shortened. As a result, the plasma density can be improved and downsizing can be achieved. A small-sized electron beam-excited plasma generation that is useful for processing technology in the electronics industry by reducing the size of the power supply, thereby reducing the overall size of the device, reducing power consumption, and improving operability. No device is provided.

[0021]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the structure of the invention of this application, which has the above-mentioned object and which is summarized in the claims, has been integrated with the preceding electron beam gun. A reaction chamber, wherein an electron beam acceleration region of the electron beam gun is provided with a former discharge electrode and a latter acceleration electrode, and a magnetic field for diffusing the electron beam incident on the reaction chamber is formed. In the plasma generating apparatus, the fact that the outer diameter of the magnet that forms the magnetic field to be diffused is made smaller than the outer diameter of the reaction chamber is one of the basics. The magnet for generating a magnetic field direction opposite to the beam converging magnet of the beam gun may be used. A beam converging magnet is arranged concentrically with respect to the electrode, and in addition, a beam converging magnet of the electron beam gun is arranged on a permanent magnet; and A first stage electron beam gun and a reaction chamber integrated therewith, a first stage discharge electrode and a second stage acceleration electrode are disposed in an electron beam acceleration region of the electron beam gun, and the incident electron beam enters the reaction chamber. In an electron beam excited plasma generator in which a magnetic field for diffusing a beam is formed, one of the key features is that the electrode has a structure capable of shortening the acceleration region. The electrodes may be arranged in a proximate shape on the discharge electrode side, or the discharge electrodes of the electrodes may be arranged in a proximate shape on the acceleration electrode side, and further, Above release If beam focusing permanent magnet electrode or accelerating the electrodes as being built,
In addition, a magnetic shield is provided on the acceleration region side of the reaction chamber, so that the magnetic shield for the reaction chamber is installed close to the reaction chamber side of the beam focusing magnet. If the electron beam gun of the former stage and the reaction chamber integrated with it were formed, the electron beam was extracted from the discharge region of the electron beam gun, accelerated, incident on the reaction chamber, and introduced into the reaction chamber. In an electron beam excited plasma generating apparatus for exciting a process gas, it is further required that the electrode shape for extracting the electron beam is formed from a solid porous electrode plate. The electron beam gun has an electron beam accelerating region, and the former has a discharge electrode and the latter has a reaction chamber. In an electron beam excited plasma generator in which an electrode is provided and a magnetic field for diffusing an incident electron beam is formed in the reaction chamber, it is different that the discharge electrode is formed from a solid porous electrode plate. It took the technical measures that were the backbone of.

[0022]

In order to perform ultra-precision dry etching of a silicon wafer forming a highly integrated circuit such as an IC or an LSI used for a device of an electronic device which performs an ultra-high-speed operation, an electron beam is used with the silicon wafer or the like as a target sample. The hot cathode filament of the electron beam gun provided beforehand in the reaction chamber of the excitation plasma generator is placed at a predetermined position via a holder, generates a hot electron, and generates a hot electron. The supplied argon gas or the like is turned into plasma by the voltage applied during, and an accelerating voltage is applied between the discharge electrode and the accelerating electrode. To the reaction chamber in the region, in the case of the discharge electrode, the central part of the electrode plate is solid and the central part A perforated plate is formed by forming an electron beam passage hole in the periphery, so that the passing electron beam does not pass through the center of the plasma region intensively, so that the center of the target sample wafer is not irradiated much, and the discharge is performed. The electrode and the accelerating electrode are arranged so that one side is relatively close to the other side, so that the size of the electron beam gun is shortened, and a magnetic field coil is provided in the support of the accelerating electrode and the discharge electrode. In addition, a magnetic shield is provided in this part, the electron beam is less scattered in the acceleration region, the acceleration electrode transmission efficiency is good, and the plasma The magnetic field lines in the region are rapidly diffused, and the electron beam is also rapidly diffused along the magnetic field lines, so that highly uniform ions are generated and electrons are distributed, and a large-diameter target is formed. The fine dry etching of the sample wafer is performed with high efficiency, the backflow of the plasma forming gas from the reaction chamber to the acceleration region is reduced, and the necessary pumping capacity of the pump in the region can be reduced. The size of the pump can be reduced, and as a result, downsizing of the acceleration region, downsizing and downsizing by advancing the wafer are promoted, and not only initial assembly at the time of manufacturing but also maintenance, inspection and maintenance during the operation period, Maintenance and operation such as management become easy, running costs as well as initial costs are reduced, equipment is simplified, durability is improved, and operation efficiency is remarkably improved.

[0023]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a first embodiment of the present invention; FIG.

The same parts as those in FIGS. 12 and 13 will be described using the same reference numerals.

In the embodiment shown in FIG. 1, reference numeral 1 'denotes a new small-sized electron beam excited plasma generator for industrial use which forms the gist of the invention of the present application, and a target sample such as a large-diameter silicon wafer. In this mode, ultra-fine dry etching using 24 plasma ions is performed, and substantially the same operation as the conventional mode shown in FIG. 12 is performed.

In this embodiment, a relatively small-diameter cylindrical electron beam gun 2 at the front stage and a relatively large-diameter cylindrical reaction chamber 3 at the rear stage are directly connected and integrated. The casings are horizontal, and these casings
The electron beam gun 2 is made of S or Al. In the electron beam gun 2, the filament 5 of the electrode 4 of the hot cathode at the base end is connected to a heating power source 6 and a port 7 is provided in the cathode region 2 '. Argon gas 8 for plasma formation is supplied in a predetermined manner as in the conventional mode.

An auxiliary electrode 9 is provided between the filament 5 and the discharge electrode 11, a power source 10 is connected between the filament 5 and the discharge electrode 11, and a discharge region is formed. 13 and the discharge electrode 1
An acceleration region is formed by connecting the power supply 12 between the first electrode 1 and the acceleration electrode 13.

The exhaust port 2 is located in front of the acceleration electrode 13.
0 is formed and connected to a predetermined exhaust pump.

The magnetic field coil 1 is located outside the discharge electrode 11.
6, a magnetic field coil 16 'is provided outside the accelerating electrode 13 in a ring shape, and a magnetic field coil 16' is provided concentrically outside the magnetic field coil 16 '. A magnetic field coil 17 'is further provided outside in a ring shape.

In the reaction chamber 3 connected to the electron beam gun 2, a chlorine gas supply port 18 is provided on the wall near the electron beam gun 2 so that the chlorine gas 1
9 to form a predetermined plasma in the plasma region 3 ', and an exhaust port 20 is provided on the opposite wall surface.
Are provided and connected to a predetermined exhaust pump.

A multipole magnet 21 is provided outside the reaction chamber 3, and a holder 23 is inserted near the inner rear end to set a target sample 24 such as a silicon wafer in a predetermined manner. Is to be
In the invention of this application, the conventional magnetic shutter 22 shown in FIG. 12 is not provided.

Reference numeral 25 denotes a probe.

In the embodiment of the present embodiment, FIG.
As in the conventional mode shown in FIG. 1, no reverse magnetic field coil 17 is provided outside the reaction chamber 3, and the magnetic field coil 16 'is concentric with the magnetic field coil 16' outside the acceleration electrode 13 at the base end of the electron beam gun 2 as described above. Further, the magnetic field coil 17 'is fitted on the outside thereof as described above to form a double coil system.

Therefore, in this embodiment, the electron beam trajectory is formed to be axially symmetric, and
As in the conventional embodiment shown in FIG. 2, in the case where the reversed magnetic field coil 17 is disposed outside the reaction chamber 3, there are few restrictions on positioning and centering, the axis alignment is accurate, and the trajectory of the electron beam is designed. And the magnetic field coil 16 ',
Further, the electron beam can be quickly diffused along the magnetic field in the plasma region 3 'of the reaction chamber 3 by the reverse magnetic field coil 17', and the electrons diffused in the radial direction are formed by the multipole magnet 21. The electron beam is efficiently reflected by the magnetic field, and as a result, the uniform dispersion of the electron beam in the plasma region 3 ', that is, the uniform irradiation of the excited sample with the flux and energy of the target sample 24 is reliably performed. Will be.

According to the invention of this application, a magnetic shield made of a predetermined material such as permalloy, low carbon steel, soft magnetic iron, or mu metal is provided on the outer wall of the reaction chamber 3 near the electron beam gun 2. 27 'is provided as appropriate to block the magnetic field lines from the magnetic field coil 16' and the reverse magnetic field coil 17 'from spreading into the reaction chamber 3;
Therefore, the diffusion of the electron beam guided into the reaction chamber 3 from the acceleration electrode 13 is performed as rapidly as possible.

Thereby, the electrons and the ions to be excited are highly uniform and spread in a large area.
Will be irradiated.

Thus, the embodiment shown in FIG.
In this embodiment, the magnetic field coil 16 ″ attached to the support 3 is supported by the acceleration electrode 13, or is housed inside the acceleration electrode 13 itself (in the illustrated embodiment, is housed inside) to form a built-in coil type. In the embodiment, the inner diameter of the coil is reduced similarly to the above embodiment, so that the plasma region 3
As the diffusion of the electron beam in the target coil 24 becomes sharp, irradiation of the target sample 24 with uniform excitation ions is performed, and the size of the magnetic field coil 16 ″ becomes smaller, so that power consumption is reduced. And electron beam gun 2
As a result, the size can be reduced as well as the size of the device becomes shorter.

In this embodiment, the acceleration electrode 13
A magnetic shield 27 'made of a predetermined material such as permalloy or low-carbon steel is attached to the rear surface of the reaction chamber 3, that is, close to the reaction chamber 3, so that entry of the magnetic field lines into the reaction chamber 3 is prevented. Similarly, rapid diffusion of the electron beam in the reaction chamber 3 is achieved, and irradiation of the highly homogenized ion beam to the target sample 24 can be achieved in the same manner.

In this case, as in the embodiment shown in FIG.
Magnetic shield 27 'having a forward-facing flange on the inner and outer edges
”, And furthermore, the supply and discharge ports 29 and 2 for the cooling water 28
9 'can be provided, and magnetic shields of a plurality of materials can be combined.

Thus, the acceleration electrode 1 of the magnetic shield is used.
As shown in FIG. 4, the distance to the inside of the reaction chamber 3 'in the extraction direction of the electron beam is represented on the horizontal axis Z (m) by the arrangement on the horizontal axis Z (m).
When the magnetic force H (Oe) Gauss is plotted on the vertical axis, as shown in the lower part of FIG. 4, a mode without a magnetic shield 27 ', a mode in which a flat magnetic shield 27''is provided, and a magnetic field with flanges at both ends. In the mode in which the shield 27 '''is additionally provided, as shown in the characteristic curve graph at the top, the magnetic force has a peak at a desired portion and is attenuated, and the restraint on the electron beam is reduced. Experiments have shown that the diffusion of the electron beam can occur rapidly.

The shape of the magnetic shield is not limited to the shape described above.
, Can be designed.

As described above, in the conventional electron beam excited plasma generator 1 shown in FIG. 12, an electron beam passage hole 26 is provided in the center of the discharge electrode 11 of the electron beam gun 2 at the center. 13, the central portion of the energy region of the electron beam having a large energy area does not spread even if it is led into the reaction chamber 3, and a target such as a silicon wafer or the like is used without the magnetic shutter 22. Although the sample 24 was directly and rapidly irradiated with the high energy component of the center of the electron beam, in the invention of this application, as in the embodiment shown in FIG. The central part of 11 is solid, and as shown in (a), a discharge electrode plate 11 'in which pores 26', 26 '... are arranged in a ring around the center, or (b) Like, a small hole 6 '' ... or a double discharge electrode plate as is bored in a ring shape 11'', as the embodiment shown in (c), radial holes 26'''
Or the electrode plate 11 '''of the through-hole 26''''' as shown in the embodiment (d) is possible. As a result, the plasma region 3 ′ of the reaction chamber 3
Since the electron beam having a high energy region is not irradiated on the axial center line of the laser beam, the electron beam is averagely diffused in the plasma region 3 ', and no magnetic shutter is required. In combination with the arrangement of the shields 27, 27 ', etc., the uniform diffusion of the electron beam can be more reliably achieved.

The embodiment shown in FIG.
A mode in which the magnetic field coil 16 corresponding to the discharge electrode 11 and the magnetic field coil 16 ″ corresponding to the accelerating electrode 13 are built in the support or the electrode itself (the illustrated mode is the built-in mode). The magnetic field coils 16, 16 '' corresponding to the inside of the discharge electrode 11 of the electron beam gun 2 and the inside of the accelerating electrode 13 are built-in as described above.
′, The diameter of the coil is small, downsizing is promoted, the transmitted electron beam is rapidly diffused in the reaction chamber 3, and the uniformity is also achieved. I can do it.

Further, since the diameters of these coils can be reduced, it is easy to increase the magnetic field strength of the electrode portion. As a result, the convergence of the electron beam is improved, and the electron beam passage hole of the electrode is reduced. It is also possible to reduce the size of the apparatus, so that the back flow of the chlorine gas 19 from the inside of the reaction chamber 3 into the electron beam gun 2 is reduced, and the capacity of the exhaust pump is reduced accordingly. , Downsizing will be promoted.

Next, in the embodiment shown in FIG. 7 (although the reversed magnetic field coil 17 is disposed outside the reaction chamber 3 'as in the conventional mode shown in FIG. 21), the functions of the above-described embodiments are performed. In order to further increase the height, the accelerating electrode 13 'is tapered forward so that the electron beam passing portion thereof is tapered forward, and is brought closer to the discharge electrode 11 side to shorten the distance between the discharge electrode 11 and the accelerating electrode 13'. When the electron beam gun 2 is shortened and the plasma region 3 'is lengthened, the target sample 24 is advanced toward the electron beam gun 2 by that amount, and the apparatus is downsized as a whole. The electron beam is not subjected to a large scattering effect and the acceleration electrode 1
In this embodiment, the transmission efficiency of 3 ′ is increased.

Therefore, in this embodiment, the acceleration electrode 13
Since the size of the electron beam transmission holes in the inside can be made small, the backflow of the chlorine gas 19 from the reaction chamber 3 to the electron beam gun 2 side is also suppressed, and the acceleration region 15
As a result, the internal gas pressure can be increased
Since the capacity of the exhaust pump can be reduced, a small pump is sufficient, and the initial and running costs associated with the downsizing of the acceleration region 15 can be reduced.

At the same time, since the accelerating electrode 13 ′ is formed in an enlarged tapered shape toward the reaction chamber 3, the acceleration of the electron beam in the reaction chamber 3 is affected by the influence of the potential of the accelerating electrode 13 ′. Diffusion is further encouraged.

The embodiment shown in FIG.
The embodiment shown in FIG. 8 is a modification of the embodiment shown in FIG. 8, in which the electron beam transmitting hole portion of the accelerating electrode 13 ′ is brought closer to the discharge electrode 11, and a magnetic field coil 16 ″ is further provided in this portion. It is built-in and combines these functions and effects.

The embodiment shown in FIG. 9 is a mode in which the magnet built in the accelerating electrode 13 'of the embodiment shown in FIG. 8 is a permanent magnet 16 ". ,
Although the direction of the line of magnetic force is reversed at a predetermined position in the axial direction of the permanent magnet 16 ″, the permanent magnet 1 built in the accelerating electrode 13 ″ by forming a magnetic field by the magnetic field coil 16 of the discharge electrode 11.
The synthesized magnetic field with 6 ″ does not reverse in the acceleration region, but reverses on the side of the plasma chamber 3 ′ of the reaction chamber. Therefore, the magnetic field lines rapidly expand in the reaction chamber 3 and follow the magnetic field lines. The introduced electron beam converges in the acceleration region 15 and rapidly diffuses in the reaction chamber 3, so that in the reaction chamber 3, ion excitation and electron beam expansion are performed uniformly, Irradiation of ions having a uniform flux and energy in the plane is performed on the target sample 24.

In the invention of this application, the magnetic field lines formed by the permanent magnets are rapidly expanded, so that it is not necessary to use the reverse magnetic field coil 17 '.

Next, in the embodiment shown in FIG. 10, the discharge electrode 11 'is opposite to the embodiment shown in FIGS.
Extends toward the acceleration electrode 13 in a tapered shape, and
5 is extended to the vicinity of the reaction chamber 3, and even in this mode, the distance between the electron beam and the acceleration electrode 13 is reduced, and the electron beam is guided to the reaction chamber 3 through the acceleration electrode 13 without being strongly scattered. The electron beam passing efficiency of the accelerating electrode 13 is improved, the size of the acceleration region is reduced and the size is reduced by reducing the capacity of the exhaust pump, the efficiency is improved, and the electron beam gun 2 is further reduced in size. This is a mode in which cost can be reduced.

Then, in the embodiment shown in FIG.
A mode in which the magnetic field coil 16 ″ corresponding to the tapered rearwardly extending discharge electrode 11 ′ of the embodiment of FIG. 10 is built in the discharge electrode 11 ′ itself or its support (the illustrated mode is a built-in type). And the magnetic field coil 16 '
In this embodiment, the power consumption is reduced, and downsizing of the device, improvement in electron beam passage efficiency, and improvement in spread can be achieved.

The embodiment of the invention of this application is not limited to the above-described embodiments. For example, in the embodiment shown in FIG. Various modes such as a permanent magnet instead of a coil and a combination of FIGS. 9 and 11 can be adopted.

The magnetic shield can be arranged on both the outer wall surface of the reaction chamber and the back surface of the accelerating electrode.

[0055]

As described above, according to the invention of this application, there is provided an electron beam excited plasma generator having various advantages as described above. The rapid diffusion of the electron beam derived from the electron beam gun in the reaction chamber is made possible by reducing the diameter of the magnet, so that the electron beam gun itself is shortened, and accordingly, the plasma chamber is reduced in scale. In order to promote uniformity due to rapid diffusion of the electron beam led to the reaction chamber, the size of the target sample is reduced. Collision of an electron beam with a high energy range is avoided, and the orbit of the electron beam is made axially symmetric, so that uniform plasma generation is obtained. Excellent effect that is can be attained.

Further, as in the conventional mode, the omission of the magnetic shutter and the omission of the holder for holding the magnetic shutter reduce the loss of electrons and ions on the surface, thereby achieving high-quality fine dry etching as designed. An excellent effect of being obtained is achieved.

Further, the bottleneck with the multipole due to the elimination of the magnetic shutter is eliminated, and from this point also, an excellent effect is obtained in that the loss of the electron beam is reduced and the homogenization by diffusion is promoted.

The position of the target sample can be moved forward by, for example, fitting a reverse magnetic field coil outside the conventional reaction chamber outside the acceleration electrode near the base of the electron beam gun. There is also an effect that the connection with the coil to be installed is easy, the centering of the positioning can be easily performed, the lines of magnetic force are formed uniformly, and the trajectory of the electron beam is formed axially symmetrically.

Further, at least one of the discharge electrode and the acceleration electrode is tapered so as to shorten the acceleration region, so that the axial length in the electron beam gun is reduced. This leads to the shortening of the beam gun, which not only shortens the entire apparatus, but also prevents the backflow of the plasma generation gas in the reaction chamber to the electron beam gun, thereby making it possible to reduce the capacity of the exhaust pump in the acceleration region. Also, downsizing and downsizing of the electron beam gun can be achieved from this point.

Further, it is possible to increase the amount of argon gas or the like introduced from the upstream portion of the electron beam gun by reducing the amount of the backflow of the plasma generation gas in the reaction chamber into the electron beam gun. And the amount of electron beam extracted from the discharge part can be increased.

When the magnets corresponding to the discharge electrode and the accelerating electrode are built-in or permanent magnets, the lines of magnetic force are rapidly expanded in the reaction chamber, and the diffusion of the electron beam along the lines is also rapidly generated. As described above, the effect of adding uniformity is also taken into account.

By arranging the magnetic shield on the side wall of the reaction chamber or on the back of the accelerating electrode, the lines of magnetic force do not enter the plasma chamber, and the rapid diffusion of the electron beam in the plasma chamber is promoted. From this point, an excellent effect that uniform ion irradiation can be performed on the target sample in the plasma chamber is achieved.

By using a porous electrode in which the electron beam transmission hole of the discharge electrode is present around the center, the irradiation of the electron beam in the high energy region along the center line toward the center of the target sample can be avoided. The ring-shaped electron beam enters the reaction chamber and interacts with the effect of electron reflection by the multipole, so that a uniform plasma can be generated even if the magnetic shutter is omitted. An obstacle such as metal contamination due to loss of electrons or ions generated in the cooling pipe or the like can be avoided, and from this point, an excellent effect that a good quality fine dry etching process can be obtained can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view of a basic embodiment of the present invention.

FIG. 2 is a partial longitudinal sectional view of another embodiment.

FIG. 3 is a schematic enlarged longitudinal sectional view of the accelerating electrode.

FIG. 4 is a model diagram of a magnetic field formation with a magnetic shield attached to an acceleration electrode.

FIG. 5 is a schematic surface view of a porous electrode of a discharge electrode.

FIG. 6 is a partial vertical sectional view of another embodiment.

FIG. 7 is an overall schematic longitudinal sectional view of another embodiment.

FIG. 8 is a partial longitudinal sectional view of still another embodiment.

FIG. 9 is a partial longitudinal sectional view of another embodiment of the present invention.

FIG. 10 is a longitudinal sectional view of an electron beam gun according to still another embodiment.

FIG. 11 is a longitudinal sectional view of an electron beam gun according to still another embodiment.

FIG. 12 is an overall schematic sectional view of a conventional electron beam excited plasma generator.

FIG. 13 is a surface view of the electrode plate of the discharge electrode.

[Explanation of symbols]

1 'small electron beam excited plasma generator 24 target sample 16, 16' magnetic field coil 23 target sample holder 17 'reverse magnetic field coil 3 reaction chamber 15 electron beam acceleration area 11 discharge electrode 13 acceleration electrode 16, 16', 16 '', 17 'magnet 16 "permanent magnet 27, 27", 27 ", 27""magnetic shield 11", 11 ", 11"",11""electrode plate

──────────────────────────────────────────────────続 き Continuing from the front page (72) Katsunobu Aoyagi, Inventor 2-1 Hirosawa, Wako-shi, Saitama Pref. (72) Inventor Makoto Ryuuji 1-1-1, Kawasaki-cho, Akashi-shi, Hyogo Kawasaki Heavy Industries Ltd. Akashi Inside the plant (72) Inventor Masato Ban, 1-1, Kawasaki-cho, Akashi-shi, Hyogo Prefecture Kawasaki Heavy Industries, Ltd. Inside the Akashi Plant Akashi Plant (72) Inventor Hiroshi An An 1-1, Kawasaki-cho, Akashi-shi, Hyogo Kawasaki Heavy Industries Inside the Akashi Plant (72) Inventor Masakuni Tokai 1-1, Kawasaki-cho, Akashi-shi, Hyogo Kawasaki Heavy Industries, Ltd. Inside the Akashi Plant (58) Fields investigated (Int. Cl. ⁶ , DB name) H05H 1 / 24 H01L 21/3065 C23F 4/00 G21K 5/04

Claims (12)

(57) [Claims] 1. A consists of a front stage of the electronic beam gun and this integrated by being the reaction chamber, the front discharge electrodes and the rear stage of the accelerating electrode is disposed on the electron beam acceleration region of the electron beam gun, the reaction chamber Incident electron beam
In the electron-beam excited plasma generator for the magnetic field to be diffused is formed a small electron beam excitation, characterized in that the outer diameter of the magnet to form a magnetic field to the spread is smaller fence than the outer diameter of the reaction chamber Plasma generator. 2. A magnet to form a magnetic field to the diffusion is the
Magnetic field direction opposite to the beam focusing magnet of the electron beam gun
Small electron beam excited plasma generator according to claim 1, wherein the magnet der Rukoto for generating. Wherein the magnet and the forming a magnetic field to the diffusion
The beam focusing magnet of the electron beam gun is
Claim 2 is characterized in that it is concentric manner provided
A small-sized electron beam excited plasma generator as described in the above. 4. A beam converging magnet of said electron beam gun.
3. The method according to claim 2, wherein the permanent magnet is disposed on a permanent magnet .
3. A small electron beam excited plasma generator according to any one of the above 3) . 5. made from the reaction chamber are integrated to the front of the electronic beam gun, the front discharge electrodes and the rear stage of the accelerating electrode is disposed on the electron beam acceleration region of the electron beam gun, in the reaction chamber the electron beam incident
An electron beam excited plasma generating apparatus in which a magnetic field to be diffused is formed, wherein the electrode has a structure capable of shortening an acceleration region. 6. A small electron beam excited plasma generating apparatus according to claim 5, wherein an accelerating electrode of said electrode is disposed in a shape close to said discharge electrode. 7. The discharge electrodes of the electrode is proximate form the accelerating electrode side
6. The device according to claim 5 , wherein the components are arranged in a shape .
6. A compact electron beam excited plasma generator according to any one of 6. 8. A beam focus in the discharge electrode or the acceleration electrode .
Claim use permanent magnets is characterized in that it is built 5
7. A compact electron beam excited plasma generator according to any one of items 1 to 7 . 9. Small electron beam excited plasma generator according to any one of claims 1-8, characterized in that the magnetic shield in the acceleration region side of the reaction chamber is provided. 10. The small electron beam excitation as claimed in claim 1, wherein a magnetic shield for said reaction chamber is installed close to said reaction chamber side of said beam focusing magnet. Plasma generator. 11. An electron beam gun comprising a former stage electron beam gun and a reaction chamber integrated therein.
An electron beam is extracted from the discharge region, accelerated, and the reaction chamber is accelerated.
Process gas introduced into the reaction chamber and introduced into the reaction chamber
In an electron beam excited plasma generator that excites
A small electron beam excited plasma generator, wherein the shape of the electrode for extracting the electron beam is formed from a solid porous electrode plate. 12. An electron beam gun of the preceding stage and an integral part thereof.
And a reaction chamber,
In the electron beam acceleration region, the former discharge electrode and the latter
A pole is provided, and the incident electron beam enters the reaction chamber.
Electron beam excitation pump with a magnetic field
In the plasma generator, the discharge electrode is a solid porous electrode.
Small electronic devices characterized by being formed from plates
Beam-excited plasma generator.