JPS6340236A - Ion source - Google Patents

Abstract

PURPOSE:To cut down primary factors of generating blur of an ion beam so as to reduce contamination of a path of the ion beam by providing an electron gun for generating the pulsing electron beam ionizing a given gas and a beam control supply for feeding a pulsing voltage. CONSTITUTION:An electron gun consists of a cathode 32 having an ion passing hole in the center of an ion supply 31 and being provided with an electron emitting surface, and a grid 33 and an outlet electrode 34, serving as an electron beam control electrode. A non-illustrated ion beam controlled and formed by said electron gun is further accelerated by an anode 35 to ionize the given gas in an ionization space between the anode 35 and an electron collector 39. Further, a pulsing control voltage is impressed between the grid 33 and the cathode 32 from a DC bias power supply 50 and a pulse power supply 51 to generate a pulsing electron beam. Thereby, without providing a deflection means and a blanking target the primary factors of generating blur of an ion beam can be cut down while reducing contamination of an ion beam path and shortening the ion beam path.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an ion source, and particularly to an ion source used in an ion beam device.

[Conventional technology]

Conventionally, this type of ion source typically generates ions continuously. For example, the duoplasmatron ion source disclosed in Japanese Patent Application Laid-Open No. 59-167944 is a typical conventional ion source, and as shown in FIG. A predetermined gas is introduced from an introduction device 64, and a plasma 67 is formed with the help of a discharge power source 65 and a stabilizing resistor 66. Then, the ion beam 70 is positively charged by the extraction electrode 69 which is set to a more negative potential than the anode 63 etc. by the acceleration power source 68.
is extracted from the plasma 67. Since the ion beam 70 is taken out continuously, in order to interrupt the irradiation of the sample, the ion beam 70 is turned in one direction and is received by a so-called blanking target (not shown).

[Problem that the invention seeks to solve]

The conventional ion source described above continuously generates an ion beam, and in order to interrupt the irradiation of the sample, the ion beam is deflected by a planking target laser. In the case of a device that uses a relatively large ion beam output (current or accelerating voltage), there are disadvantages in that the planking targeter 1~ is severely damaged and the ion beam path is easily contaminated.

Another drawback is that the configuration and arrangement of the deflection system must be appropriate in order to prevent this deflection from causing blurring of the ion beam at the sample irradiation position.

Furthermore, the provision of the above-mentioned deflection system and blanking target has the disadvantage that it becomes an obstacle to further shortening the ion beam path and improving the quality of the ion beam.

It is an object of the present invention to
It is an object of the present invention to provide an ion source which can reduce the causes of blurring of an ion beam without requiring the provision of an ion beam, reduce contamination of the ion beam path, and shorten the ion beam path.

[Means for solving problems]

The ion source of the present invention includes a cathode having an ion passage hole in the center of an electron emission surface, an extraction electrode facing the cathode, and an electron beam control electrode provided between the cathode and the extraction electrode, and includes an electron gun that generates a pulsed electron beam that excites gas ionization;
It is configured to include a beam control power source that supplies a pulsed voltage between the electron beam control electrode and the cathode.

[Effect]

Next, the operation of the present invention will be explained with reference to the drawings.

FIG. 3 is a cross-sectional view of the ion source for explaining the operating principle of the present invention.

In FIG. 3, electrons emitted from a cathode 32 having an ion passage hole are extracted by an extraction electrode 34, and further accelerated by an anode 35 as an ionizing electron beam 36.
The gas introduced from the gas introduction device 38 is ionized in an ionization (plasma) space 37 between the anode 35 and the electron collector 39 .

The ionization space 37 is an equipotential space and it is advantageous to provide a focusing coil 44 in order to extend the specific travel distance of the ionization electron beam 36 entering it and increase the chances of ionization.

Positive ions are extracted from the plasma consisting of ions and electrons formed in the ionization space 37 by the extraction electrode 34,
An ion beam 45 is obtained that passes through the ion passage hole of the cathode 32 and travels downward in the figure.

The potential of the grid 33 as an electron beam control electrode arranged in the space between the cathode 32 and the extraction electrode 34 is set to the cathode 3
When the potential of 2 is set to a predetermined negative value, electron beam emission can be controlled by so-called triode action, and by applying a pulsed voltage from the pulsed power source 51, the ionizing electron beam 36 is pulsed. It is possible to generate

With this pulsed electron beam, the ion beam 45 can also be generated in a pulsed manner. In FIG. 3, exhaust ports 41, 42, and 43 are connected to respective vacuum exhaust systems, and function to bring each electrode and ionization space into a predetermined vacuum state.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional perspective view of an ion beam apparatus using an embodiment of the present invention.

The ion beam apparatus shown in FIG. 1 includes an ion source 31 and an ion beam optical system 52.

In FIG. 1, an ion source 31 has an ion passage hole in the center, and electrons are formed by controlling an electron gun consisting of a cathode 32 with a rectangular electron emitting surface, a grid 33 as an electron beam control electrode, and an extraction electrode 34. The beam (not shown) is
It is further accelerated by the anode 35 to ionize a predetermined gas (for example, evaporated material of the electron collector 39) in the ionization space between the anode 35 and the electron collector 39.

The focusing coil 44 causes the electron beam to perform a spiral motion, thereby increasing the effective travel distance of the electron beam and increasing the ionization efficiency.

A pulsed control voltage is applied between the grid 33 and the cathode 32 from a DC bias power supply 50 and a pulsed power supply 51, thereby generating a pulsed electron beam.

The ion beam 45 generated by this pulsed electron beam is then extracted from the ionization space by the extraction electrode 34, passes through the central hole of the cathode 32, and enters the ion beam optical system 52.

The pulsed ion beam 45 generated by the ion source 31 is focused by the condenser lens 3 and passes through the Win filter 4.
A crossover is formed at approximately the center of the sample, and then the objective lens 6 focuses its image on the target 7 on the sample stage 14, and the target 7 is processed and processed.

In the Win filter 4, the effect of deflecting the ion beam 45 by the magnetic field formed between the S magnetic pole plate 8 and the N magnetic pole plate 9 is exactly canceled by the electric field between the electrostatic deflection plates 10.1.1. Only the ion species of ion pass through the hole of the aperture 5. A ion species 12 and B with different specific charges (charge/mass)
The ion species 13 are blocked by the aperture 5 and do not reach the target 7.

Therefore, the target 7 can be processed and processed using a pulsed ion beam composed of only specific ion species.

〔Effect of the invention〕

As explained above, the ion source of the present invention generates an intermittent ion beam instead of a continuous ion beam, thereby eliminating the need for a blanking target or the like. This has the effect of reducing contamination of the ion beam path due to this.

Furthermore, by omitting the blanking deflection system and the blanking target, the degree of freedom in configuring the ion beam optical system is increased and the factors that cause ion beam blur can be reduced.

The above-mentioned advantages are particularly noticeable when processing or processing a sample by applying a relatively high-output ion beam to the sample.By being pulsed, it is possible to suppress the temperature rise of the sample and improve the accuracy of processing and processing. There is also this effect.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional perspective view of an ion beam apparatus using an embodiment of the present invention, FIG. 2 is a cross-sectional view of an example of a conventional ion source,
FIG. 3 is a cross-sectional view of the ion source for explaining the operating principle of the present invention. 3... Condenser lens, 4... Win filter,
5...Aperture, 6...Objective lens, 7...Targera 1~. 8...S [pole plate, 9...N magnetic pole plate, 10.11
...Electrostatic deflection plate, 12...A ion species, 13...
B ion species, 14... sample stage, 31... ion source,
32...Cathode, 33...Grid, 34...
Extraction electrode, 35... Anode, 36... Ionization electron beam, 37... Ionization space, 38... Gas introduction device, 39... Electron collector, 41, 42.43
... Exhaust port, 44... Focusing coil, 45... Ion beam, 50... Bias power supply, 51... Pulse power supply, 52... Ion beam optical system, 61... Cathode, 62 ... intermediate electrode, 63 ... anode, 64
...Gas introduction device, 65...Discharge power supply, 66...
Stabilizing resistor, 67... Plasma, 68... Accelerating electric current 1
N5. )′

Claims (1)

[Claims] A pulse pulse for ionizing and excitation of a predetermined gas in an ionization space, comprising a cathode having an ion passage hole in the center of an electron emission surface, an extraction electrode facing the cathode, and an electron beam control electrode provided between the cathode and the extraction electrode. An ion source comprising: an electron gun that generates a shaped electron beam; and a beam control power source that supplies a pulsed voltage between the electron beam control electrode and the cathode.