JP2627069B2 - Charged particle irradiation device - Google Patents

Description

The present invention relates to an ion microbeam apparatus provided with an ion beam irradiation mechanism, an electron microscope provided with an ion beam irradiation mechanism and an electron beam irradiation mechanism, an exposure apparatus, and the like. And a charged particle irradiation apparatus.

[Conventional technology]

For example, metal materials, various gas ions or metal ions from an external ion source is injected into a thin film of a semiconductor material or the like to analyze lattice defects thereof, or to a sample that is a furnace wall material of a fusion reactor, for example. An electron microscope is used for performing various analyzes by implanting He ions. In addition, microscopic observation is possible while irradiating the ion beam accelerated by the accelerator to the sample in the microscope, and the change in the lattice behavior of the material that changes due to ion irradiation can be directly observed. Electron microscopes are also very effective in measuring microscopic phenomena governing various phenomena.

FIG. 5 shows a part of a conventional electron microscope used for performing such analysis and the like.

The ion beam accelerated by the ion beam accelerator (not shown) is electrostatically deflected by the electrostatic deflector 2 and is introduced into the electron microscope from the ion beam introduction port 9 fixed to the electron microscope housing wall 5. You. The sample 6 is irradiated with the introduced ion beam through the hollow portion of the pole piece 4 of the objective lens for focusing the electron beam Eb. In such an electron microscope, the electron beam _Eb is perpendicularly incident on the surface of the sample 6, and the ion beam _Ib is obliquely incident. In order to detect whether the ion beam _Ib is actually generated and passing through the drift tube 10, there is provided a Faraday cup 11 which can be inserted into the ion beam path from a vacuum chamber 10A provided in the middle of the drift tube 10. ing. The Fuaradeikatsupu 11 operating rod 12 and leads to the outside by, by operating only the operation rod 12 when it is desired to detect the ion beam I _b, is inserted into the ion beam passageway. And when the detection is not required of the ion beam I _b are retracted into the vacuum Chiyanba 10A, and summer so as not to adversely affect the ion beam I _b. Such an ion beam detection mechanism is the same in other charged particle irradiation apparatuses.

[Problems to be solved by the invention]

However, when such a conventional charged particle irradiation system, while the alignment detection of the ion beam I _b by Fuaradeikatsupu 11, since it can not be irradiated with the ion beam I _b to the sample 6, the ion for sample 6 It took a lot of time to adjust the beam position.

[Means and actions for solving the problems]

In the present invention, in order to eliminate such a drawback, an endless electrode composed of an annular or cylindrical first and second endless electrodes that surrounds a part of the axis of the ion beam 360 degrees is used as a casing of the charged particle irradiation apparatus. Have in the body. The use of this endless electrode, the hollow portion of the endless electrode ion beam I _b
Is adjusted to pass, and further adjusted so that the ion current detected by colliding with the endless electrode is minimized.
The ion beam can be easily aligned with the sample by a very simple means. Further, the second endless electrode disposed between the pair of first endless electrode, the pair of first endless electrode due to the influence of the ion beam I _b generated around the second endless electrode Absorbed secondary electrons or floating ions,
Since these effects are eliminated and the ion current is detected from the second endless electrode, high-precision detection can be performed. Therefore, the detection signal can be used not only for high-accuracy ion beam alignment, but also for other purposes. Can also be used for purposes. further,
The convergence of the ion beam can be improved by using the endless electrode.

[Embodiment] An embodiment of an electron microscope in an electron beam irradiation apparatus according to the present invention will be described with reference to FIG. 1. An electrostatic prism system 2 of an ion beam irradiation mechanism 1 is an electron lens system 3 in an electron microscope main body. And is fixed to the electron microscope housing wall 5 in a space between the objective lens and the ball piece 4 of the objective lens. The electrostatic deflection system 2 includes a first electrode for deflecting the ion beam.
2a and a second electrode 2b, the first located at both ends of these electrodes,
The second slits 2c and 2d, the support 2e for supporting the electrodes 2a and 2b, and the static electric field formed by the high DC voltage applied between the electrodes 2a and 2b do not adversely affect the electron beam. It comprises a shield member 2f for electrostatically shielding the electrodes 2a, 2b and the like. Here, the slit 2c, the support 2e, and the shield member 2f are fixed to the electron microscope housing wall 5. Further, the first and second electrodes 2a and 2b are formed of two metal plates, for example, stainless steel plates, each of which is obtained by cutting a part of two concentric sphere walls having different sizes into appropriate strips.

Well, where the outlet of the ion beam I _b in the electrostatic deflector 2 has an endless electrode 8 is set to a position suitable for alignment in advance ion beam is provided, this endless electrode later More specifically, a conductive tube 7 having a tubular cavity centered on the same axis as the ion beam is coupled to the sample side. The conductive tube 7 is made of a non-magnetic material such as phosphor bronze, stainless steel, copper, or a ceramic material having extremely good conductivity, or a magnetic material such as permalloy. One end thereof is opposed to the endless electrode 8 provided on the output side of the electrostatic deflection system 2 so that the axes thereof coincide with each other as described above, and the other end extends to the hollow portion of the pole piece 4 of the objective lens. ing. Thus, it is desirable that the tip of the conductive tube 7 extends to the vicinity of the sample 6 as long as it does not adversely affect the electron beam.
Accordingly, the ion beam electrostatically deflected by the electrostatic deflection system 2 irradiates the sample 6 through the inside of the conductive tube 7. At this time, since the conductive tube 7 is fixed at the connection potential and shields the ion beam from the electric field and the magnetic field in the casing, the ion beam _Ib is influenced by the electrostatic field and the magnetic field in the casing of the charged particle irradiation apparatus. No convergence, so the convergence is hardly reduced.

By detecting the amount of ions to be a trap to by connexion the electrode endlessly electrode 8 where, to detect the deviation of the position of the ion beam I _b to be irradiated to the sample 6, the ion current detected is zero, or the lowest value to become such that the lens system (not shown) and the electrostatic deflection system 2 to adjust the deflection of the ion beam I _b. By so doing, it facilitates the alignment of the ion beam I _b for sample 6.

Next, referring to FIG. 2, an endless electrode according to the main components of the present invention will be described. The one shown in FIG. 2A is composed of three annular electrodes 8A, 8A ', 8B. Each of these three annular electrodes has the same shape and size, and is made of stainless steel with an inner diameter of 2 mm, an outer diameter of 6 mm, and a width of 2 to 4 mm. The annular electrodes 8A and 8A 'located on the outside are connected to the ground potential point,
The annular electrode 8B located at the center is connected to the charged particle measuring device 16 via the external terminal 15. A pair of first annular electrodes 8
A, 8A 'absorbs secondary electrons or floating ions are generated around the second annular electrode 8B by the influence of the ion beam I _b, eliminate their effects, improve the measurement accuracy of the ion beam It is to make it. The ions trapped by the central annular electrode 8B disposed between the pair of first annular electrodes 8A and 8A 'flow through the external terminal 15 as an ion current to the charged particle measuring device 16 and are detected. . By looking at the value of the meter of the charged particle measuring instrument and adjusting one or both of the voltage and the current of the lens system (not shown) and the electrostatic deflection system 2 so that the value becomes the minimum, Sample 6
It is alignment of the ion beam I _b for.

The endless electrode 8 shown in FIG. 3B is a cylindrical electrode 8A, 8A '.
The cylindrical electrode 8A, 8A 'is connected to a ground potential point, and the annular electrode 8B is connected via an external terminal 15 to a DC power supply for applying a DC voltage + V. The DC voltage + V differs depending on the magnitude of the energy of the ion beam _Ib , but may be a DC voltage of about 1 kV or less. By applying an appropriate DC voltage to the annular electrode 8B located at the center in this way, the ion beam _Ib is focused.
Accordingly, the sample can be irradiated with an ion beam having a high energy density, and the rate of irradiation of the surface other than the sample with the ion beam is reduced, so that contamination can be reduced.

Next, the endless electrode 8 shown in FIG. 3C is composed of two annular electrodes 8A, 8A 'and an annular electrode 8B, and the annular electrodes 8A, 8A are formed.
A 'is connected to the ground potential point, and cylindrical electrode 8B is connected to external terminal 1
It is selectively connected to either the charged particle measuring device 16 or the DC power supply 18 via 5 and the switch 17. In this case, when measuring the ion beam _Ib , the switching switch 17 is used.
Is connected to the cylindrical electrode 8B between charged particle measuring device 16, switch 17 switched in a state where the ion beam I _b is irradiated on the sample 6 is connected to an annular electrode 8B to the DC power supply 18.

Next, FIG. 4D shows the endless electrode as shown in FIG. 4A, and a ring electrode 8B 'having a smaller diameter than the other endless electrodes 8A, 8A', 8B is provided in the axial direction of the ion beam. The annular electrodes 8A and 8A 'are fixed to the ground potential, the annular electrode 8B is connected to the DC power supply 18, and the annular electrode 8B' is connected to the charged particle measuring device 16, respectively. Although not shown, these annular electrodes are insulated by an insulating material such as a glass ceramic material which hardly generates gas.

Next, another embodiment of the present invention will be described with reference to FIG. 3. In this embodiment, the tip of the conductive tube 7 in the embodiment shown in FIG. 1 is shown in FIGS. 2 (A) to 2 (C). Such an endless electrode 8 'is further provided, and the endless electrode 8 is connected to a DC power supply, and the endless electrode 8' is connected to a charged particle measuring instrument. Ion beam I _b from the electrostatic deflection system 2'm connexion focused degree endlessly electrodes 8 is increased, the ion beam I _b elevated of this degree of focusing is carried out the registration measurement by charged particle measuring device. Here, when the ion beam _Ib is an intermittent beam, not only the ion beam alignment detection is performed, but also the Auger electrons generated from the sample 6 by the irradiation of the ion beam during the idle period of the ion beam _Ib , Secondary ions, secondary electrons, etc. can be detected.
Such detection is made possible because the endless electrode 8 'is arranged near the sample 6.

Another embodiment of the present invention shown in FIG.
Is located outside the housing wall 5 of the charged particle irradiation device, and the tip of the conductive tube 7 fixed to the housing wall 5 has a shape as shown in any of FIGS. 2 (A) to 2 (D). And the endless electrode 8 and related members are provided. The operation of this apparatus is almost the same as that of the above embodiment, and therefore, the description will be omitted.

〔The invention's effect〕

As described above, according to the present invention, the second endless electrode is disposed between at least the pair of first endless electrodes, and the pair of first endless electrodes is in contact with the second endless electrode under the influence of the ion beam. Absorbs secondary electrons or floating ions generated around the endless electrode, eliminates their influence, and detects substantially only the ionic current by the second endless electrode. Ion beam detection can be performed.

Further, at least when it is desired to detect the ion beam, the second endless electrode located in the middle is selectively connected to the charged particle measuring device, and is fixed to the second endless electrode during the period when the ion beam is not detected. By applying this voltage, highly accurate ion beam detection can be performed, the convergence of the ion beam can be improved, and contamination can be reduced.

[Brief description of the drawings]

FIG. 1 is a view showing an embodiment of a charged particle irradiation apparatus according to the present invention, and FIGS. 2 (A) to 2 (D) illustrate examples of endless electrodes used in the charged particle irradiation apparatus according to the present invention. FIGS. 3 and 4 are views showing another embodiment of the charged particle irradiation apparatus according to the present invention, and FIG. 5 is a view for explaining a conventional charged particle irradiation apparatus. DESCRIPTION OF SYMBOLS 1 ... Ion beam irradiation mechanism, 2 ... Electrostatic deflection system 3 ... Electronic lens system 4, ... Pole piece of objective lens 5 ... Case wall, 6 ... Sample 7 ... Conductive tube, 8, 8 '... Endless electrode 9 ... Ion beam introduction port 10 ... Drift tube

Claims (1)

(57) [Claims] An ion beam irradiation mechanism provided around an ion beam path for irradiating a sample and having an endless electrode for detecting the ion beam current and an electrostatic prism system for deflecting the ion beam. In a charged particle irradiation apparatus that adjusts the deflection of the ion beam with the electrostatic prism system to align the axis of the ion beam so that the value of the ion beam current detected by the endless electrode is reduced. The endless electrode is located between a pair of first endless electrodes fixed at a constant potential in order to improve the measurement accuracy of the ion beam, and is located between the pair of first endless electrodes, and at least. A charged particle irradiation apparatus, comprising: a second endless electrode connected to an external terminal connected to a charged particle measuring device when measuring an ion beam.