JPS6132940A - Liquid metal ion source - Google Patents

Abstract

PURPOSE:To prevent the ion source material evaporated from an ion generating source from being condensed in an ion acceleration electrode and the pollution resulting from the ion source material from affecting the ion acceleration electrode and such by heating the ion acceleration electrode, lens system, and the wall of the ion source container. CONSTITUTION:A resistance heating mechanism 12 that uses a tungusten heater is mounted on an ion acceleration electrode 3, lens system 6, and ion source container 9 and a cooling panel 14 connected to a liquid nitrogen collector 13 is arranged. After vacuum is exhausted, a trap mechanism that uses a cooling panel 14 and the resistance heating mechanims 12 are operated. As a result, the ion source material evaporated from the ion generating source is trapped in the cooling panel instead of being condensed in the ion acceleration electrode and such. Consequently, an ion beam 7 normally actuates on a sample 8. In addition, the ion source material is not polluted by the heating of an observation window and the observation of the inner part of the ion source cannot be prevented.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a liquid metal ion source device, and is designed to prevent contamination of ion accelerating electrodes, lens systems, ion source container walls, exhaust systems, etc. by ion source materials. Relating to an ion source configured.

[Background of the invention]

FIG. 1 shows an example of a conventional liquid metal ion source.

This type of liquid metal ion source is, for example, JP-A-59-
It is described in Publication No. 31541. The ion generation source includes a chip heating filament 1, an emitter chip 2, an ion accelerating electrode 3, a crucible 5 holding an ion source material 4, and the like. The crucible 5 coaxially holds a rod-shaped emitter chip 2 with a pointed tip, and the bottom wall of the crucible 5 has an opening through which the tip of the emitter tip 2 passes through to the outside. An ion source material is loaded on the outer periphery of the tip of the chip 2 . Reference numeral 6 denotes a lens system consisting of one or more lenses (only one lens is shown) that focuses the ion beam 7. 8 is a sample irradiated with the ion beam 7; 9 is an ion source container and a vacuum exhaust system 10, Ii
l! It is equipped with 11 viewing windows.

The conventional device as shown in FIG. 1 having the above-described configuration operates as follows. After evacuation, heat the filament 1,
As a result, the tip of the emitter tip 2 is heated by thermal radiation. When the tip of the emitter tip 2 is heated, the ion source material 4 is heated and melted by thermal conduction, and the ion source material 4 is continuously supplied to the tip of the emitter tip 2. On the other hand, the tip of the emitter tip 2 is heated, and the ion source material 4 is ionized, which is extracted as an ion beam 7. The extracted ion beam is controlled by a lens system 6 and irradiated onto a sample 8.

In the conventional liquid metal ion source described above, the ion source material evaporated from the ion beam 7 and the periphery of the tip of the emitter chip 2 is transferred to the ion accelerating electrode 3, the lens system 6, the wall of the ion source container 9, the observation window 11, etc. The ion accelerating electrode 3 and the lens system 6 are prevented from functioning properly, and internal observation through the observation window 11 becomes difficult. .

[Purpose of the invention]

An object of the present invention is to provide a liquid metal ion source that solves the above-mentioned problems in liquid metal ion sources and prevents contamination of the ion accelerating electrode, lens system, etc. of the ion source material.

[Summary of the invention]

A feature of the present invention is that in a liquid metal ion source, the ion accelerating electrode, lens system, and wall of the ion source container are heated;
The purpose is to prevent the ion source material evaporated from the ion generation source from condensing on the ion accelerating electrode, etc., and to prevent contamination by the ion source material from reaching the ion accelerating electrode, etc.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIG. This is a conventional device shown in FIG. 1 in which a resistance heating mechanism 12 using a tungsten heater is attached to an ion accelerating electrode 3, a lens system 6, and an ion source container 9, and a cooling panel 14 connected to a liquid nitrogen reservoir 13 is further arranged. It is.

The operating principle is as follows. After vacuum evacuation, cooling panel 1
4, the trap mechanism and resistance heating mechanism 12 are operated. Thereafter, the ion generation source is operated, the ion beam 7 is extracted, and the operation up to irradiation of the sample is the same as that of the conventional apparatus shown in FIG.

The ion source material evaporated from the ion source is subjected to ion addition,
It does not condense on the fast electrodes and is trapped on the cooling panel.

As a result, the ion beam 7 acts normally on the sample 8. In addition, heating of the observation window eliminates contamination of the ion source material, and the t! A-san will not interfere. For example, when this ion source was applied to ion implantation, it was possible to implant ions as intended.

In the above embodiment, an ion generation source having an emitter tip and a crucible is used, but other types such as a type that uses only a crucible without using an emitter tip, a type that uses only an emitter tip without using a crucible, etc. It can be applied to general liquid metal ion sources.

In addition, in the above embodiment, a resistance heating mechanism using a tungsten heater was used as an acceleration mechanism for the ion accelerating electrode, etc., but heating using an infrared lamp heating laser, heating using an electron beam, etc. Any material that can be heated to a certain temperature will suffice.

Furthermore, instead of heating using a fixed heating source, the heating source may be a movable one, and it is also effective to provide means for selecting the heating position.

Furthermore, in the above-described embodiment, a cooling panel connected to a liquid nitrogen reservoir was used as the trap mechanism, but any mechanism capable of condensing the evaporated ion source material may be used. In addition to this embodiment, the trap mechanism may also be installed at the lens position, near the accelerating electrode, or near the sample.

In addition, in the above embodiments, ion implantation was mentioned as an application example of this ion source, but other application examples include ion beam processing, ion beam exposure, and measurement using ion beams. It can be applied to various devices using ion sources.

〔Effect of the invention〕

According to the present invention, in a liquid metal ion source, contamination of other ion source components by the ion source material evaporated from the ion generation source or the ion beam can be prevented by the heating mechanism and the trap mechanism. can act normally on the sample as intended.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of a main part of an ion source as a conventional example, and FIG. 2 is a vertical cross-sectional view of a main part of an ion source according to an embodiment of the present invention. ■...Filament, 2...Emitter chip, 3...
...Ion accelerating electrode, 4...Ion source material, 5...
Crucible, 6... Lens system, 7... Ion beam, 8.
... Sample, 9... Ion source container, 10... Vacuum exhaust system, 11... Observation window, 12... Resistance heating mechanism, 13
...Liquid nitrogen reservoir, 14 1 Figure

Claims (1)

[Claims] 1. In a liquid metal ion source comprising a liquid metal ion generation source, an ion accelerating electrode, and a lens system for focusing the ion beam, a heating mechanism for the ion accelerating electrode, the lens system, the wall of the ion source container, etc. A liquid metal ion source comprising: 2. The liquid metal ion source according to claim 1, further comprising a mechanism for trapping evaporated ion source material. 3. The liquid metal ion source according to claim 1, further comprising a mechanism that allows the trap to be cooled from the outside of the device independently of other heating parts.