JPH05205681A - Ion source device - Google Patents

Abstract

PURPOSE:To eliminate eccentricity in the energy distribution and the surface density of ion beam to be drawn out from plasma and control the heading of the ion beam precisely by splitting a drawout electrode into a plurality of electrode fragments on one plane, and giving different potentials to these electrode fragments. CONSTITUTION:A drawout electrode 2 is formed from a plurality of electrode fragments 2a-2d concentrically on a circumference on one plane, and a number of thin holes 1 are provided over the whole area of the fragments 2a-2d. An electrode supporting insulative plate 3 is the base board of the electrode 2 and is made of ceramic material such as alumina. Different potentials are given by a power supply 4 to these fragments 2a-2d, and the potential is heightened outward little by little from the center of the electrode 2. An isopotential plane 5 is generated between the electrode 2 and a metal electrode 6. The heading of a moving charged particle, which receives a force in the direction along the line of electric force as perpendicular to the isopotential plane 5, can be varied into the direction along a line perpendicular to the center of the electrode 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ion source device for extracting ions from plasma to obtain an ion beam,
In particular, the present invention relates to an ion source device capable of accurately controlling the direction of an ion beam by eliminating the deviation of the surface density and energy distribution of the ion beam.

[0002]

2. Description of the Related Art Generally, an ion source device has a structure in which ions are extracted from plasma generated by direct current or high frequency discharge by extraction electrodes to obtain a positive ion beam or a negative ion beam. As a conventional example of such an ion source device, for example, the device disclosed in JP-A-61-75527 can be cited.

FIG. 8 is a cross-sectional view of the structure of an etching apparatus using a conventional ion source device.

In this figure, 9 is a plasma generating chamber 11
The gas introduced through the introduction port 9 is turned into plasma in the plasma generation chamber 11, passes through the ion extraction electrode 18, and is introduced into the exhaust system 15 through the sample chamber 21. It is designed to be exhausted.
Further, 16 is a microwave introduction window provided in an opening formed in the plasma generation chamber 11, 7 is a rectangular waveguide for microwave introduction attached to the window 16, and 17 is electron cyclotron resonance. It is a magnetic coil for generating a magnetic field necessary to cause it.

In the etching apparatus having such a structure, the plasma generated in the plasma generating chamber 11 passes through the ion extraction electrode 18 formed of, for example, three mesh-shaped electrode plates 18a to 18c, and a shower-shaped ion beam is formed. And is guided to the sample chamber 21 provided adjacent to the plasma generation chamber 11. A sample table 19 is provided in the sample chamber 21.
Is provided, on which the sample 20 to be etched is placed. Therefore, the shower-like ion beam guided from the plasma generation chamber 11 to the sample chamber 21 as described above irradiates the sample 20 on the sample table 19 with ions, and thus the sample 20 is etched. Done.

By the way, in the above-mentioned conventional example, when the ion beam is extracted from the plasma, one or more plate-like electrodes such as a metal mesh or a punching metal with open pores are arranged so as to be in contact with the plasma, A voltage was applied to the electrode to extract positive ions and negative ions. The electrode is usually called an extraction electrode, and a voltage may be applied to the plasma generation chamber itself that generates plasma, and the extraction electrode may be grounded.

Further, the extraction electrode usually has a planar structure, and the potential inside one extraction electrode is constant.
However, depending on the shape of plasma generation, the ion beam extracted from the plasma may have an uneven surface density distribution,
The ion energy distribution may be biased. Therefore, when performing some kind of processing using such an ion beam, the deviation of the areal density distribution or the ion energy distribution may affect the processed shape and may cause a problem.

In order to solve such a problem, for example, as disclosed in JP-A-55-122342,
It has also been attempted to deform the extraction electrode three-dimensionally by forming it into a spherical shape having a certain radius of curvature.

Further, changing the shape of the extraction electrode in this way is also performed when the ion beam extracted from the plasma is converged, as shown in Japanese Patent Laid-Open No. 56-45600. It was

[0010]

However, when the surface density and energy distribution of the ion beam are made uniform or the shape of the extraction electrode is changed in order to focus the ion beam as in the above-mentioned conventional example, it is possible to identify However, it is necessary to form the shape of the extraction electrode in accordance with the surface density of the ion beam, the bias of the energy distribution, and the direction of the ion beam, which makes it extremely difficult to process the electrode.

Further, as shown in an enlarged view in FIG. 9, when a plurality of extraction electrodes 22 and 23 are used, pores 22a to 22c and 2 for extracting the ion beam 25 from the plasma 24 are used.
Unless 3a to 23c are correctly aligned, the trajectory of the extracted ion beam 25 is deflected according to the deviation of these pores. The diameters of the pores 22a to 22c and 23a to 23c are
Usually, it is about several tens of microns to several millimeters. For this reason, it is very difficult to use two or more extraction electrodes and to precisely overlap the positions of the pores, and to change the three-dimensional structure of the electrodes to make the areal density of the ion beam uniform. Had become difficult. Therefore, it is possible to manufacture if one extraction electrode is used, but it is completely impossible to manufacture if a plurality of extraction electrodes having a non-planar structure are stacked.

In view of the above situation, the present invention has been made to solve the above-mentioned drawbacks and the like of the conventional example, and eliminates the deviation of the areal density and energy distribution of the ion beam extracted from the plasma. It is an object of the present invention to provide an ion source device capable of accurately controlling the direction of the ion.

[0013]

SUMMARY OF THE INVENTION The present invention provides an ion source device having a plurality of divided electrode pieces on the same surface, each of which is provided with a different potential. In both cases, the above problem is solved by providing one ion extraction electrode.

Similarly, the present invention solves the above-mentioned problems by disposing a plurality of the above-mentioned ion extraction electrodes in an ion source device so as to face each other.

Similarly, the present invention solves the above problem by disposing one undivided electrode in the ion source device so as to face the ion extraction electrode.

[0016]

The present invention operates as follows. That is, in the present invention, at least one ion extractor having a plurality of electrode pieces divided into a plurality of parts on the same plane (flat surface or curved surface) and applying different potentials to each of the electrode pieces is provided. Electrodes are provided so that the ion extraction electrode can eliminate the bias in the areal density and energy distribution of the ion beam extracted from the plasma.

Therefore, the structure of the ion extracting electrode is simple and easy to manufacture, and the ion beam extracted from the plasma can be controlled accurately and easily.

[0018]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIGS. 1 and 2 are explanatory views of the structure of the main part of the present embodiment. FIG. 1 shows the planar structure of a flat lead electrode which is the main part of the present embodiment, and FIG. -A 'cross section is shown.

In FIG. 1, the extraction electrode 2 has electrode pieces 2a to 2d which are divided into a plurality of concentric circles on the same plane.
And a large number of pores 1 are provided on the entire surface of each of the electrode pieces 2a to 2d.

The electrode supporting insulating plate 3 shown in FIG. 2 is a substrate for the extraction electrode 2 and is made of a ceramic material such as alumina. It should be noted that the large number of pores 1 corresponds to the electrode piece 2
It is provided so as to penetrate a to 2d and the electrode supporting insulating plate 3.

The flat lead electrode 2 having such a structure is manufactured as follows. That is, a large number of pores 1 are provided in a substrate made of an insulating ceramic material such as alumina, and metal is concentrically deposited on the substrate to form the electrode pieces 2a to 2d. In this case, when stainless steel, nickel, or the like is used as the metal, the ion beam can be extracted with less wear of the extraction electrode 2 even from plasma generated by using a halogen-based corrosive gas.

FIGS. 3 and 4 are views for explaining the equipotential surface relating to the present embodiment, in which 2'is a lead electrode similar to the lead electrode 2 and 3'is an electrode supporting insulating plate 3. Similar electrode supporting insulating plates, 4 and 4'indicate power sources, 5 and 5'indicate equipotential surfaces, and 6 indicate a single flat metal electrode.

In FIG. 3, a plurality of divided electrode pieces on the same plane are provided with different potential differences, and the extraction electrode 2 as described in detail with reference to FIGS. 1 and 2 and one flat metal. The electrodes 6 are arranged so as to face each other, and the equipotential surface 5 is formed. That is, the concentric electrode pieces 2a to 2d shown in FIGS.
Among them, different potentials are applied to the electrode pieces so that the potentials become higher from the center of the extraction electrode 2 toward the outside, and the equipotential surface 5 is formed between the extraction electrode 2 and the metal electrode 6. .. Further, when the equipotential surfaces are distributed in this way, the movement direction of the charged particles which receives a force in the direction of the electric force line perpendicular to the equipotential surface 5 is a line perpendicular to the center of the extraction electrode 2. Can be changed in the direction of.

On the other hand, in FIG. 4, two lead electrodes 2 and 2'as detailed in FIGS. 1 and 2 are arranged so as to face each other, and an equipotential surface 5'is formed. By arranging the two extraction electrodes 2 and 2'to face each other in this way, the equipotential control range can be made wider than in the case of FIG. 3, and as a result, the ion beam direction control range can also be made wider. be able to.

In this case, a DC voltage power source is used as the power sources 4 and 4 ', and the absolute value of the divided voltage applied to the plurality of electrode pieces is kept constant with the relative ratio of the applied voltage to each electrode piece kept constant. The kinetic energy of the charged particles can be changed by changing the state as it is.

In this way, the direction and energy of the ion beam extracted from the plasma by the extraction electrodes 2, 2'can be controlled.

The electrode pieces of the extraction electrodes 2 and 2'do not necessarily have to be divided by the dividing method described in detail in FIG. 1, and, for example, depending on the shape and energy of the ion beam to be generated. You may change the division method.

FIG. 5 and FIG. 6 are explanatory views of the structure of the main part of another embodiment of the present invention. FIG. 5 shows the planar structure of the arcuate lead electrode, which is the main part of the embodiment, and FIG. A- in FIG.
A'section is shown. Further, in FIGS. 5 and 6, the same symbols as those in FIGS. 1 and 2 are used with the same meanings, and the duplicated description is omitted here.

As is apparent from FIG. 6, the extraction electrode 2 in this embodiment does not have a flat planar structure as in the case of FIG. 2, but an arcuate curved surface structure. In this way, since the extraction electrode 2 itself does not have a planar structure,
Even if different potentials are not applied to the divided electrode pieces 2a to 2d, the ion beam extracted from the plasma has a direction corresponding to the three-dimensional structure of the extraction electrode 2. Also, FIG.
As shown in FIG. 3, the divided electrode pieces 2a to 2d are concentric with each other in common with the embodiment of FIG.

By the way, an ion source device in which the extraction electrode does not have a planar structure and the shape of the electrode can be changed is disclosed in, for example, Japanese Patent Application Laid-Open No. 55-1223 shown in FIG.
Although it is disclosed in Japanese Patent Publication No. 42, the adjustment is not easy.

That is, in FIG. 10, the filament 23
When a current is supplied to the gas, electrons are emitted due to the thermoelectron effect, and the gas introduced from the gas inlet 24 is ionized. Next, the arc voltage applied to the vacuum wall 25 causes an arc current to flow in the ionized gas to cause heating, and the heated ionized gas is turned into plasma. Then
The plasma is accelerated and converged through the acceleration electrode 26, the deceleration electrode 27, and the ground electrode 28.

As is apparent from FIG. 10, in order to keep these electrodes 26 to 28 parallel, an insulating spacer 30a is used.
, 30b and the respective surfaces of the electrode supports 29a to 29c must be precisely parallelized. Further, in order to keep the distance between the electrodes 26 to 28 accurately, the members 29a to 29c, 30
The surface dimensions a to 30b must be precise. Furthermore, among the three electrodes 26 to 28, the directions of the holes provided in the electrodes are aligned, and the members 29a to 29c are aligned.
, 30a to 30b must be precisely adjusted in the radial direction, which requires an extremely large number of processing steps, and adjustment of the ion source device has not been easy.

On the other hand, in the case of the ion source device of the present invention described in detail with reference to FIGS. 1 to 6, since the extraction electrode 2 is divided into a plurality of electrode pieces 2a to 2d, etc. The area density and energy distribution of the ion beam and the direction of the ion beam can be controlled very easily by simply changing the potential of the. Further, since the mechanical structure of the extraction electrode 2 is not changed in these controls, such control can be performed accurately.

FIG. 7 is a structural explanatory view of a usage example of the present invention, and is a structural sectional view of a dry etching apparatus using the extraction electrode 2 according to the present invention.

In this figure, FIGS. 1 to 6 and 8 to 1
The same symbols as those used for 0 are used with the same meanings, and duplicate explanations are omitted here.

Further, 8 is a magnetron as a microwave source, 10 is an electromagnet, 13 is a substrate holder for holding the substrate 12, and 14 is an etching reaction chamber.

In the use example of the present invention having such a structure, ECR plasma is generated in the plasma generation chamber 11, and the ion beam is extracted from the plasma by the extraction electrode 2. Further, the relative value of the voltage applied to the extraction electrode 2 is adjusted so that the direction of the ion beam is changed to the substrate 12.
Should be perpendicular to. Furthermore, the extraction electrode 2
The absolute value of the applied voltage is adjusted while keeping the relative ratio of the applied voltage between the divided electrode pieces constituting the above.

With this adjustment, the energy of the ion beam was adjusted, and good etching could be performed in the etching reaction chamber 14.

[0040]

According to the present invention described in detail above, the extraction electrode is divided into a plurality of electrode pieces on the same surface,
By giving a potential difference to each of the electrode pieces, it is possible to eliminate the bias in the areal density and energy distribution of the ion beam extracted from the plasma and control the direction of the ion beam.

Therefore, there is an advantage that the structure of the extraction electrode is simple and the production is extremely easy, and the ion beam extracted from the plasma can be controlled accurately and easily.

[Brief description of drawings]

FIG. 1 is a plan view showing a planar structure of a flat lead electrode, which is an essential part of an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a cross section taken along the line AA ′ of FIG.

FIG. 3 is a diagram for explaining an equipotential surface when the extraction electrode of FIG. 1 and a flat metal electrode are arranged so as to face each other.

FIG. 4 is a diagram for explaining an equipotential surface when two extraction electrodes of FIG. 1 are arranged so as to face each other.

FIG. 5 is a plan view showing a planar structure of an arc-shaped lead electrode, which is a main part of another embodiment of the present invention.

6 is a cross-sectional view showing a cross section taken along the line AA ′ of FIG.

FIG. 7 is a structural explanatory view of a usage example of the present invention.

FIG. 8 is a cross-sectional view of a configuration of an etching apparatus using a conventional example.

FIG. 9 is an enlarged view for explaining the deviation of pores.

FIG. 10 is a configuration cross-sectional view for explaining another conventional ion source device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Pore, 2 ... Extraction electrode, 2a-2d ... Electrode piece, 3 ... Electrode supporting insulating plate, 4, 4 '... Power supply, 5, 5' ... Equipotential surface, 6 ... Metal electrode, 7 ... Waveguide , 8 ... Magnetron, 9 ... Gas introduction tube, 10 ... Electromagnet, 11 ... Plasma generating chamber, 12 ... Substrate, 13 ... Substrate holder, 14 ... Etching reaction chamber, 15 ... Vacuum exhaust system.

Claims (3)

[Claims] 1. An ion source device for extracting ions from plasma to obtain an ion beam, comprising a plurality of divided electrode pieces on the same surface, and applying different potentials to each of these electrode pieces. An ion source device comprising at least one ion extraction electrode. 2. The ion source device according to claim 1, wherein a plurality of the ion extraction electrodes are arranged to face each other. 3. The ion source device according to claim 1, wherein one undivided electrode is arranged so as to face the ion extraction electrode.