JPH01149347A - Electron gun - Google Patents

Abstract

PURPOSE:To provide controllability for the shape of an electron beam without use of any electron-optical lens by forming the electrode system including filament, grid, and anode either concentrically or in a concentrical curvature. CONSTITUTION:A filament 1, beam shaping electrode (grid) 4, and beam accelerating electrode (anode) 6 are arranged concentrically with the point 0 as the center. Accordingly the filament 1, grid 4, and anode 6 are on concentrical circles with radii RK, RG, RA with the point 0 as the center, and electron beam is emitted radially from the filament 1, as shown in attached illustration, so that the shape of the beam is wider than in a conventional arrangement. This permits control of the electron beam shape without use of an electron-optical lens.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an electron gun, and more particularly to an electron gun for electron beam evaporation.

(Prior Art) Electron guns generate electron beams, and are used in electron microscopes, electron beam lithography devices, and the like. In this type of apparatus, a sample is irradiated with an electron beam emitted from an electron gun, and the reflected signal is captured and reproduced as an image, or the beam itself is used to expose a material such as a wafer.

By the way, the energy ratio of the backscattered electron signal that irradiates and reflects the material to the incident beam varies depending on the material (sample), and increases as the atomic number Z increases, reaching 40 to 50%.
There are some materials (such as tungsten) that cause most of the incident energy to become heat.

For example, if the beam is narrowed down, this heat can be reduced to 1 million KW/
It also becomes possible to generate heat at a density as high as cm2. Therefore, when a sample (material) such as metal is irradiated with such an electron beam, the surface of the sample (material) such as metal can be melted and evaporated.

A vacuum evaporation apparatus is an apparatus that performs metal evaporation on the surface of a material by utilizing the evaporation phenomenon of materials such as metals caused by electron beams.

FIG. 5 is a diagram showing an example of the conventional configuration of an electron gun used for vacuum evaporation as described above. In the figure, 1 forms a cathode with a linear filament.

A common potential (a negative electrode in the case of a DC power source) of an acceleration power source 2 and a filament power source 3 is applied to one end of the filament 1. Since the positive side of the acceleration power supply 2 is grounded, an extremely high negative voltage (acceleration voltage) is applied to the filament 1.
It will cost.

Reference numeral 4 denotes a beam shaping electrode (grid) arranged oppositely along the filament 1, and a negative potential of a grid power source 5 whose positive polarity side is connected to the negative electrode of the acceleration power source 2 is applied to the grid.

The positive electrode side of the filament power supply 3 is connected to the other end of the filament 1. 6 is a beam accelerating electrode (anode) arranged opposite to the filament 1, and is grounded. A slit 6a is provided in the center of the beam accelerating electrode 6 for passing the generated electron beam. 8 is a gold rfR (sample) for metal deposition; 9 is a crucible containing the metal 8; cooling water 10 is circulated at the bottom of the crucible;

Further, the crucible 9 is grounded.

In the device configured in this way, when a current is passed through the linear filament 1 from the filament power supply 3, the filament 1 generates heat and emits thermoelectrons. The generated thermoelectrons pass through the slit 6a of the beam accelerating electrode 6 and are accelerated. Here, the device shown in the figure includes a magnetic field generator (not shown).
For example, a ring coil) generates a magnetic field B in the direction of the arrow, and the electrons passing through the slit 6a receive a force that follows Fleming's left hand side, causing the beam trajectory to rotate as shown in the figure, resulting in a bundle of electron beams Bi. metal 8 in crucible 9
It collides with the surface in a linear fashion.

Then, the part where the electron beam Bi collides is gradually heated, the metal melts, and the metal evaporates. Here, the metal vapor generated is extremely fine particles at the atomic or molecular level. Metal vapor deposition can be performed by placing a member to be vapor-deposited (for example, glass, metal, etc.) above the vacuum where the metal is evaporating.

(Problems to be Solved by the Invention) Using such an electron gun (linear filament type electron gun, hereinafter abbreviated as LPG), a large output (several tens of kilowatts or more) and a large deflection (at least 90 degrees or more. - Generally speaking, 180°~27
There was no established method to control the beam shape at the irradiation surface of 0'). That is, the length of the filament is large (
(several 10 m+ or more), the use of a normal axially symmetric electro-optical lens is accompanied by considerable structural difficulties. The above-mentioned beam deflection angle means the bending angle of the emitted beam, and the situation is shown in FIG.

The present invention has been made in view of these points, and
The purpose is to realize an electron gun that can control the electron beam shape without using an electron optical lens.

(Means for Solving the Problems) The present invention, which solves the above problems, provides an electron gun having a linear filament.

This is characterized in that the shape of the electrode system constituting the electron gun, such as the grid and anode, is concentric or concentrically curved.

(Function) The shape of the electrode system consisting of a filament (cathode), a beam shaping electrode (grid), and a beam accelerating electrode (7 nodes) is concentric or concentrically curved. As a result, as shown in FIG. 7, the width of the electron beam emitted from the filament 1 is increased, and the shape of the electron beam can be changed without using an electro-optical lens.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a mechanical configuration diagram showing an embodiment of the present invention.

Components that are the same as those in FIG. 5 are designated by the same reference numerals. still,
In the figure, the power supply and its potential connection diagram are omitted. As is clear from the figure, the structure of the electrode system is the same as the conventional example shown in FIG. The difference is that except for crucible 9, filament 1. The beam shaping electrode 4 and the beam accelerating electrode 6 are both arranged on concentric circles centered on the point O.

That is, filament 1. The beam shaping electrode 4 and the beam accelerating electrode 6 form part of a circle centered on point 0, that is, form an arc.

FIG. 2 is a diagram schematically showing the arrangement of the electrode system.

In this way, centering on point O, each electrode (cathode 1. grid 4. anode 6) has a radius RK, R(
,, exist on concentric circles of RA. As the electron beam is emitted radially from the cathode (filament) 1 as shown in the figure, the beam shape is larger than that of the conventional one. Here, the relationship RK≦Re, <RA exists between the radii RK, R, and R^ of each electrode.

FIG. 3 is a schematic diagram of a high-output deflection LPG according to the present invention,
(a) is a front view, and (b) is a side view.

Electron beam B emitted from filament (cathode) 1
i is grid 4. After passing through the anode 6, the metal 8 in the crucible 9 is subjected to a force following Fleming's left hand side due to the existing magnetic field B, and is subjected to a large deflection of 270° as shown in the figure.
is irradiated. The irradiated point of the metal 8 is heated and melted to generate metal vapor.

In the above-mentioned embodiment, as shown in Fig. 2, the structure of the electrode system is constructed in a convex shape when viewed from the filament side, but a concave structure (R^<R, ≦RK) is also possible. be. Further, in the above-described embodiments, the electrode system is arranged concentrically, but the structure is not limited to concentric circles, but may be any group of curved surfaces or polygons arranged parallel to each other. Fourth
The figures show other configuration examples of the electrode system, in which (a) shows a curved surface that is not concentric, and (b) shows a polygon. In the figure, A represents an anode, G represents a grid, and K represents a cathode.

In the above embodiment, an application example was explained for a directly heated electron gun using direct current heating, but it can also be applied to a directly heated electron gun using alternating current heating or an indirectly heated electron gun such as an electron impact type. It is.

(Effects of the Invention) As described above in detail, according to the present invention, the electrode system consisting of the cathode (filament), the grid (beam shaping mold 1), and the anode (beam accelerating electrode) is arranged concentrically or close to it. By configuring the shape, it is possible to realize an electron gun that can control the shape of the electron beam without using an electron optical lens.

[Brief explanation of the drawing]

FIG. 1 is a mechanical configuration diagram showing an embodiment of the present invention, FIG. 2 is a diagram schematically showing the arrangement of an electrode system, FIG. 3 is a schematic diagram of a high output deflection LPG according to the present invention, and FIG. 4 is a diagram showing another example of the configuration of the electrode system, FIG. 5 is a diagram showing an example of the configuration of the conventional device, and 61i! ! I is an explanatory diagram of the deflection angle of the electron beam, 7th
The figure shows the radiation state of an electron beam. 1... Filament 4... Beam shaping electrode 6
... Beam accelerating electrode 8 ... Metal 9 ... Crucible patent applicant Japan Electronics Co., Ltd.
Company representative Patent attorney Fuji Ijima 1 person outside the womb (a) @ 1 curved body in Shinen
(b) Polygon Figure 5 Section 2 O Figure 3 Figure 6 Figure 7

Claims (1)

[Claims] An electron gun having a linear filament, characterized in that the shape of an electrode system constituting the electron gun, such as a filament, a grid, and an anode, is concentric or concentrically curved.