JPS6345735Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an ion beam generator used for surface analysis and ion etching.

In a type of surface analysis in which the sample surface is irradiated with an ion beam and ions, electrons, etc. emitted from the sample are detected, the ion beam is focused to a beam diameter of about 1 nm to 2 μm and is made incident on the sample surface. On the other hand, in ion etching in which the sample surface is etched by ion bombardment, a beam diameter of about 1 mm to 10 mm is used.

As the beam diameter varies greatly depending on the purpose of the ion beam, conventionally different ion guns have been used for each purpose. That is, an ion gun for surface analysis and an ion gun for ion etching were provided in one vacuum vessel so that one sample could be irradiated with ion beams obtained by the two types of ion guns. With such a configuration, the directions of incidence of the two types of ion beams on the sample are different, and accurate analysis information may not be obtained in some cases. For example, if the ion beam for surface analysis is made perpendicular to the sample surface, and the ion beam for ion etching is made to irradiate the sample surface obliquely, the sample surface will be etched by ion etching while the ion beam will be etched in the depth direction from the sample surface. When proceeding with the analysis, there may be areas where the sample surface is delayed in etching, such as areas that are shadowed when viewed from the ion gun for ion etching due to unevenness on the sample surface, or areas that are hidden by inclusions where ion etching progresses slowly. However, there are cases where accurate analysis in the depth direction cannot be performed.

The present invention aims to solve the above-mentioned drawbacks of the conventional technology.The present invention aims to solve the above-mentioned drawbacks of the conventional technology. To provide an ion gun that appears to be irradiated with an ion beam from a single ion gun.

The ion gun of the present invention includes a first ion source, a converging lens, an objective lens, and a penetrating lens, which is arranged between the convergent and objective lenses to provide a small beam diameter, and the ion beam formed by the first ion source penetrates through the ion gun. and a second ion source having holes. The present invention will be explained in detail with reference to Examples below.

The figure shows an embodiment of the invention. 1 is the first ion source, 2 is the converging lens, 3 is the second ion source, 4
is the objective lens and 5 is the sample. Both the converging lens and objective lens use electrostatic lenses. X
is the optical axis of the ion optical system, and the first and second ion sources and both the converging and objective lenses are all arranged on the same optical axis X. In the first ion source 1, a
In the ionization chamber, gas is supplied from the gas introduction hole b. A filament f1 and a grid g1 are arranged in the ionization chamber, and ions are generated by collision between accelerated electrons and gas between the filament f1 and grid g1. s1 is the first
A voltage is applied between the aperture and the ionization chamber a, and ions generated in the ionization chamber are attracted to the aperture s1, drawn out, and accelerated. The converging lens 2 forms an image of the first aperture s1 by the ion beam at point F1. In the second ion source 3, A is an ionization chamber to which gas is supplied from a gas introduction hole B.
An aperture hole sh is bored in the rear wall of the ionization chamber A, centered at the intersection with the optical axis X, and the ion beam starting from the first ion source 1 passes through the ionization chamber A of the second ion source 3. can do. In the ionization chamber A, f2 is a filament, g2 is a grid, and ions are generated in the same manner as in the first ion source 1. s2 is the second aperture, and a voltage is applied between it and the ionization chamber A, and the ions generated in the ionization chamber A are accelerated by the electric field between the ionization chamber A and the aperture s2, forming an ion beam. do.

When using an ion beam with a narrow beam diameter in the above configuration, the filament f1 in the first ion source 1 is energized, an electron acceleration voltage is applied between f1 and the grid g1, and the ionization chamber a and the first aperture s1 are
An ion accelerating voltage is applied between. On the other hand, the second
In the ion source 3, the filament f2 is not energized, no voltage is applied between f2 and the grid g2, and no voltage is applied between the ionization chamber A and the second aperture s2. Therefore, no ions are generated in the second ion source 3, and in terms of ion optics, the aperture hole sh on the rear wall of the ionization chamber A only acts as an ion beam aperture; It's basically the same as not existing. In this state, the objective lens 4 forms an image of the convergence point F1 of the ion beam formed by the first ion source 1 on the sample surface 5. The converging lens 2 and the objective lens 4 constitute a two-stage reduction projection system, and a reduced image of the first aperture s1 is formed on the surface of the sample 5. When the power of the converging lens 2 is changed, the F1 point moves left and right, and the closer the F1 point is to the aperture hole sh, the more the ion current incident on the sample 5 increases. When using an ion beam with a large beam diameter, the first ion source 1 is not activated, but the second ion source 3 is activated. In this case, since only the objective lens 4 acts as a converging lens for the ion beam formed by the second ion source 3, the image on the surface of the sample 5 of the second aperture s2 has a small reduction ratio. It becomes an ion beam with a large diameter. Note that 6 is an ion beam deflection electrode.

In the above embodiments, a hot cathode type first ion source is used, but a hollow cathode type source using a cold cathode may also be used.

The ion gun of the present invention has the above-mentioned configuration, and the ion beam with a narrow beam diameter and the ion beam with a wide beam diameter have the same optical axis, so the sample irradiation angles of the two types of beams are different as mentioned at the beginning. This problem has been resolved, and since the first and second ion sources are located in one line of sight when viewed from the sample, the empty space around the sample has become larger, making it possible to perform many functions related to sample analysis and surface treatment. It becomes possible to arrange the device.

[Brief explanation of the drawing]

The drawing is a side view of an embodiment of the present invention. 1... First ion source, 2... Converging lens, 3
...Second ion source, 4...Objective lens, 5...
Sample, a, A...Ionization chamber, f1, f2...Filament, g1, g2...Grid, s1...
First diaphragm, s2...Second diaphragm, sh...A diaphragm hole bored in the rear wall of the ionization chamber A.

Claims (1)

[Scope of utility model registration request] The first ion source, the convergent lens, and the objective lens constitute a reduction projection system for the ion beam formed by the first ion source, and the ion beam formed by the first ion source is formed between the convergent lens and the objective lens. An ion gun characterized in that a second ion source having a through hole through which an ion beam passes through is arranged around the optical axis of the reduction projection system.