JPH01169858A - Charged particle beam device - Google Patents

Abstract

PURPOSE:To shorten the working distance between an objective lens and a target and improve the convergence characteristic of a charged particle beam by concurrently using a deflecting electrode as a gas feeding pipe. CONSTITUTION:A deflecting means 21 to change the radiation point of a charged particle beam 1 on a target and a pipe 17 to guide the gas to the surface of the target are provided. The deflecting means 21 is constituted of multiple deflecting electrodes 21a-21h arranged axially symmetrically with the optical axis 0 of the charged particle beam 1, at least one 21a of the deflecting electrode is concurrently used as the gas guiding pipe 17. Since the deflecting electrode of an electron beam is concurrently used as the gas pipe, the working distance can be shortened, the convergence characteristic of the electron beam can be improved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a charged particle beam device that irradiates a target with an electron beam or an ion beam, and in particular, it relates to a charged particle beam device that irradiates a target with an electron beam or an ion beam. The present invention relates to a charged particle beam device suitable for etching a target by spraying a metal oxide, or performing deposition by spraying an organic metal gas.

[Prior art] Fig. 3 shows that while irradiating a target with an electron beam,
This figure shows a gas-assisted etching device that sprays chlorine gas, and numeral 1 in the figure represents an accelerated electron beam generated from a charged particle beam source (not shown). Reference numeral 2 denotes an electrostatic type objective lens, and the objective lens 2 is composed of an outer electrode 3 at a ground potential and a center electrode 5 to which a lens voltage is applied from a lens power source 4. 6 is an electrostatic deflection plate in the x direction, 7 is an electrostatic deflection plate in the Y direction, 8 is a target to which the electron beam 1 is irradiated, 9 is an auxiliary electrode, and 10 is an electrostatic deflection plate for the target 8 and the auxiliary electrode 9. This is the power source that provides beam deceleration potential. 11 is a microchannel plate for detecting secondary electrons generated when the electron beam is irradiated to the target 8; 12 is a detection electrode; the secondary electron emission surface 11b of the microchannel plate 11; is maintained at the same potential as the detection electrode 12, and a voltage of 1 to 1.2 kV is applied from a power source 13 between the emission surface 11b and the secondary electron incident surface 11a of the microchannel plate. Further, a voltage of about 100 V is applied from a power source 14 between the target 8 and the secondary electron incident surface 11a. The secondary electron detection signal obtained from the detection electrode 12 is amplified by a preamplifier 15 and supplied to a light emitting diode 16. 17 is a gas supply pipe connected to a chlorine gas source (not shown), and 18 is a needle valve for controlling the amount of gas blown from the pipe 17 to the target 8.

One is a shield tube, which prevents the electric field in the electron beam path from being disturbed due to movement of the target, preventing the electron beam from being improperly deflected, and preventing the focusing of the electron beam from being disturbed.

In the configuration as described above, the electron beam 1 is irradiated onto the target 8, and chlorine gas is supplied to the electron beam irradiation point of the target 8 via the gas pipe 17, so that the electron beam is irradiated. The target area is etched.

The electron beam irradiation point on the target is set by an electrostatic deflection plate 6.
It is possible to change the voltage according to the voltage supplied to the electrode 7, thereby making it possible to perform fine pattern etching. Here, the electron beam 1 is accelerated with an accelerating voltage of, for example, -30 kV, and enters the objective lens 2 with relatively high energy, so that the electron beam 1 is narrowly focused on the target B.

Here, a deceleration voltage of, for example, -27 kV is applied to the target 8 and the auxiliary electrode 9 from the power source 10, and as a result, a gap between the outer electrode 3 at the ground potential of the objective lens 2 and the auxiliary electrode 9 is applied. An electric field is formed to decelerate the electron beam, and the energy of the electron beam is lowered and the target 8 is irradiated with it. That is, the acceleration voltage of the electron beam irradiated onto the target 8 is substantially -3 kV.

In this way, in the apparatus shown in FIG. 4, the electron beam enters the electrostatic lens in a high energy state and is narrowly focused, while the electron beam is delivered to the target 8 with a low energy that is optimal for gas-assisted etching. will be irradiated.

In the apparatus shown in FIG. 4, secondary electrons generated by irradiating the target 8 with an electron beam are guided to the microchannel plate 11 and amplified, and the electrons emitted from the microchannel plate 11 are transferred to the detection electrode 12. It is detected by The signal from the detection electrode 12 is sent to the amplifier 1
5 is amplified by the target 8 and then supplied to the light emitting diode 16.
It emits light depending on the electron intensity. Light from the diode is detected by a photodetector (not shown). As a result, the electron beam 1 is scanned by the deflection plate 6.degree. 7, and the focus state of the electron beam on the target 8 can be known from the secondary electron signal detected in accordance with the scanning.

[Problems to be Solved by the Invention] In the configuration as described above, the deflection plates 6 and 7, the microchannel plate 11, and the gas supply pipe 17 are arranged between the objective lens 2 and the target 8, Inevitably, the distance (working distance) between the objective lens 2 and the target 8 becomes large, and therefore there is a limit to improving the focusing characteristics of the electron beam. Although we have described a gas-assisted etching device that uses an electron beam, in a gas-assisted etching device that uses an ion beam, there are also deflection plates, microchannel plates, gas pipes, etc. between the objective lens and the target, just like in the case of electron beams. are arranged, and the focusing characteristics of the ion beam are not necessarily satisfactory. Furthermore, not only gas-assisted etching equipment (but also gas-assisted deposition equipment that supplies organometallic gas to the irradiation point of electron beams and ion beams) has a long working distance for the same reason, making it difficult to improve the beam focusing characteristics. has its limits.

The present invention has been made in view of the above-mentioned points, and an object of the present invention is to provide a charged particle beam device that can improve the focusing characteristics of electron beams and ion beams.

[Means for Solving the Problems] A charged particle beam device based on the present invention includes a focusing lens for focusing a charged particle beam generated from a charged particle beam source and accelerated, and the charged particle beam is irradiated with the focusing lens. In a charged particle beam apparatus comprising a target, a deflection means for changing the irradiation point of the charged particle beam on the target, and a pipe for guiding gas to the surface of the target, the deflection means is used to change the irradiation point of the charged particle beam. It is characterized in that it is composed of a plurality of deflection electrodes arranged axially symmetrically about the optical axis, and at least one of the plurality of deflection electrodes is configured to also serve as the gas introduction pipe.

[Example] An embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a sectional view of a main part showing an embodiment of the present invention, and FIG. 2 is an enlarged cross-sectional view taken along line A-A in FIG. . Components in the figure that are the same or similar to those in FIG. 3 are given the same numbers, and detailed explanation thereof will be omitted.

This embodiment differs from FIG. 3 in that instead of the deflection electrodes 6 and 7 disposed between the objective lens 2 and the microchannel plate 11, eight deflection electrodes 21a to 21h are placed between the microchannel plate 11 and the microchannel plate 11. A specific electrode 21 is placed between the target 8 and the eight deflection electrodes.
a was used as a gas supply pipe. The eight electrodes 21 are arranged axially symmetrically about the optical axis 0, and the following voltages are applied to each electrode.

21a...-■× 21 b-(-Vx+Vy)/F7 21c...Vy 21 d ・= (V x + V y ) / ('
T"'21e...Vx 21 f・(Vx-Vy),'-rT21 (ko・
.;-vy 21 h . . . --(VX+Vy)/ff By applying this voltage, the deflection electric field on the optical axis has eight-fold symmetry. That is, the electron beam is deflected by an ideal deflection electric field up to the order of fifth-order approximation. Note that the structure of the tip of the electrode 21a, which is also used as a gas supply pipe, is different from that of the other electrodes 21b to 21h, so the electric field may be disturbed. By doing so, the 8-fold symmetry of the deflection electric field can be maintained.

With this configuration, compared to the conventional device shown in Figure 3, since the gas pipe and the electron beam deflection electrode are both used, the working distance can be shortened, and the focusing characteristics of the electron beam can be improved. can. Note that the secondary electrons generated from the target 8 enter the secondary electron incident surface 11a of the microchannel plate 11.
than the voltage applied to the deflection electrodes 21a to 21h.
It can be detected by applying a high voltage.

Although the embodiments of the present invention have been described above in detail, the present invention is not limited to these embodiments and can be modified in many ways.

For example, although the description has been given of an apparatus that etches a target by spraying an active gas such as chlorine gas onto the target surface, the present invention can also be applied to a gas-assisted deposition apparatus that sprays an organic metal gas. Further, although the case where an electron beam is irradiated has been described, the present invention can also be used when a target is irradiated with an ion beam. Furthermore, the number of deflection electrodes was set to 8 in order to obtain the best deflection characteristics, but if there is no need to pay special consideration to the deflection characteristics, any number other than 8 may be used as long as the condition of axial symmetry is satisfied. It may be. Furthermore, although the electron beam is decelerated, deceleration of the charged particle beam is not an essential requirement in the present invention.

[Effects] As detailed above, in the present invention, since the deflection electrode and the gas supply pipe are combined, the working distance between the objective lens and the target can be shortened, and the charged particle beam can improve the focusing characteristics of

[Brief explanation of the drawing]

1 and 2 are cross-sectional views of one embodiment of the present invention;
The figure shows a conventional gas assisted etching apparatus. 1...Electronic lens 2...Objective lens 3...
・Outer electrode 5...Center electrode 4.10.13
．． 14...Power supply 6.7...Electrostatic deflection plate 8...Target 9...Auxiliary electrode 11...
・Microchannel plate 12...detection electrode
15...Amplifier 16...Light emitting diode 17
... Pipe 18 ... Needle valve 19 ... Shield tube 21a to 21h ... Deflection electrode

Claims (3)

[Claims] (1) A focusing lens for focusing the accelerated charged particle beam generated from the charged particle beam source, a target to be irradiated with the charged particle beam, and a device for changing the irradiation point of the charged particle beam on the target. In a charged particle beam device comprising a deflection means and a pipe for guiding gas to the target surface, the deflection means is constituted by a plurality of deflection electrodes arranged axially symmetrically with respect to the optical axis of the charged particle beam. A charged particle beam apparatus characterized in that at least one of the plurality of deflection electrodes is configured to also serve as the gas introduction pipe. (2) The charged particle beam device according to claim 1, wherein an electron detector is disposed between the objective lens and the plurality of deflection electrodes. (3) Claim 1 in which eight deflection electrodes are provided.
Charged particle beam device as described in .