JPS636846Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention particularly relates to an ion source that can generate a stable ion beam.

EHD (Electro
The capillary type or capillary needle type is used for the Hydro Dynamics type field ion source depending on the properties (viscosity) of the liquid metal. The present invention relates to the latter ion source. As a capillary needle type ion source, an apparatus as shown in FIG. 1, for example, is provided. In the figure, 1 is a reservoir for storing a liquid metal such as cesium 2, and 3 is a capillary made of a thin metal tube (for example, stainless steel). Reference numeral 4 denotes a needle-like member made of, for example, tungsten, installed in the capillary 3. One end of the needle-like member 4 is fixed to the inner wall of the reservoir 1 by spot welding 5 or the like, and the other end is fixed by electrolytic polishing. A tip portion 4a is formed and disposed facing the ground electrode 6. In the above configuration, when the reservoir 1 is heated by a heating means (not shown) and a positive high voltage is applied to the reservoir 1 and the needle member 4 from a power source (not shown), the reservoir 1 is heated.
The cesium 2 inside passes through the capillary 3 due to the strong electric field of the tip 4a of the needle-like member 4, and is transferred to the tip 4.
It is pulled out to a. The cesium 2 at the tip forms a conical protrusion called Taylor's cone due to the strong electric field created by applying a high voltage between the needle member 4 and the electrode 6 at ground potential. Form. The electric field concentrates at the tip of this conical protrusion, and the cesium 2 at the tip becomes the cesium ion 1 that has been evaporated by the electric field.
It becomes B and is drawn out. In this case capillary 3
The positional relationship between the tip of the needle 4 and the tip 4a of the needle 4, and contaminants on the surface of the needle 3 have a significant effect on the characteristics of this ion source (ion emission characteristics). By the way, as a conventional method for manufacturing an ion source, as shown in FIG. 2, a needle-like member 4 made of tungsten is passed through the capillary 3, and one end of the needle-like member 4 is attached to the inner wall of the reservoir 1 by spot welding 5 or the like. It is fixed by. Next, pass the other end protruding from the capillary 3 through the ring-shaped electrode 7, and connect it to the ring-shaped electrode 7.
After depositing an electrolytic solution 8 of NaOH (sodium hydroxide) as shown in FIG. Tip part 4a as shown in the figure
is formed. The emitter composed of the reservoir 1, capillary 3, and needle member 4 finished in this manner has the following drawbacks.

Contaminants C during electrolytic polishing are placed on the top of the tip 4a of the needle member 4 that has been electrolytically polished with the electrolytic solution 8.
adheres and solidifies, obstructing the flow of liquid metal such as cesium 2.

Since the surface of the needle-shaped member 4 inside the capillary 3 cannot be electrolytically polished, it cannot be made into a clean surface with a metallic luster, and "wetting" with the liquid metal 2 occurs.
The so-called poor affinity makes the transfer resistance of the liquid metal 2 high.

The positional relationship between the needle tip 4a and the capillary 3 is determined by the position of the ring electrode 7, and since the other end is fixed by spot welding 5, the distance l between the capillary 3 and the tip 4a is determined by the position of the ring electrode 7. cannot be adjusted, and transfer resistance (Flow
conductance) cannot be adjusted.

For this reason, it has been difficult to obtain stable ion emission using conventional ion sources.

The present invention was developed in view of the above points, and consists of a reservoir section that stores the metal to be ionized, a capillary section that communicates with the reservoir section and supplies liquid metal, and a needle-like member that penetrates the capillary section. In a capillary needle type ion source, a needle-like member passing through the capillary is bent at a plurality of locations, and the needle-like member is fixed to the capillary by the frictional force between the capillary and the bent portion of the needle-like member. It is characterized by

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

FIG. 4 is a schematic diagram showing an embodiment of the present invention. The same parts as in FIG. 1 are given the same numbers and their explanations will be omitted. In the figure, numeral 10 is an embodiment of the needle-like member of the present invention. The needle-like member 10 is inserted into the capillary 3 in a shape bent at a plurality of places as shown in FIG.
A certain amount of frictional force is generated between the needle-like member 10 and the inner wall of the needle member 10, and the needle-like member 10 is fixed by this frictional force.

By the way, in order to construct this structure, as shown in FIG. When a certain voltage is applied between the needle-shaped member 10 and the ring-shaped electrode 7, electrolytic polishing is performed to form a tip. Next, by moving the needle-like member 10 as shown by the arrow in FIG. 5a, only the surface of the needle-like member 10 is electrolytically polished.
A clean surface with metallic luster can be obtained, and so-called affinity with liquid metal is improved. Therefore, the transfer resistance of the liquid metal becomes low, and the liquid metal can be stably transferred to the tip of the needle member 10. Furthermore, FIG. 5b is a diagram showing a bent portion of the electrolytically polished needle-like member 10 inserted into the capillary 3, and this bending is shown when the needle-like member 10 is inserted into the capillary 3. , is for fixing by the frictional force generated between the bent portion and the inner wall of the capillary 3. Further, to adjust the distance l between the tip of the needle member 10 and the capillary 3, the needle member 10
Apply force to the tip of the reservoir side and move it in and out of the capillary.

As described above, when the tip of a needle member used in a capillary needle type ion source is formed by electrolytic polishing, the present invention removes contaminants adhering to the upper part of the tip, and By electrolytically polishing the surface of the member to give it a clean surface with metallic luster, liquid metal can be stably transferred. Furthermore, by bending the needle-like member inserted into the capillary, the needle-like member is fixed to the capillary, and by making it possible to adjust the distance l between the capillary and the tip of the needle-like member, a stable iobeam can be produced. Obtainable.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of a conventional capillary needle type ion source, Fig. 2 is a diagram for explaining the manufacturing method of a conventional ion source, Fig. 3 is a partially enlarged view of a conventional ion source, and Fig. 4 is a schematic diagram of a conventional capillary needle type ion source. The figure is a schematic diagram of an embodiment of the ion source according to the present invention, and FIGS. 5A and 5B are diagrams for explaining a method of manufacturing the apparatus of the embodiment of the ion source according to the present invention. DESCRIPTION OF SYMBOLS 1...Reservoir, 2...Liquid metal, 3...Capillary, 4...Acicular member, 5...Welding part, 6...
... Ground electrode, 7 ... Ring-shaped electrode, 8 ... Electrolyte solution, 9 ... AC power supply, 10 ... Needle-shaped member.

Claims (1)

[Scope of utility model registration request] In a capillary needle type ion source, the ion source is composed of a reservoir section that stores the metal to be ionized, a capillary section that communicates with the reservoir section and is supplied with liquid metal, and a needle-shaped member that penetrates the capillary section. A metal ion source characterized in that the needle-like member is bent at a plurality of locations to fix the needle-like member to the capillary by a frictional force between the capillary and the bent portion of the needle-like member.