JPH0212377B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a linear electron beam heat treatment apparatus for heat treating samples such as conductors, semiconductors, dielectrics, etc. by irradiating electron beams.

(Prior art and its problems) When heat-treating a material, processing capacity is greater when the shape of the electron beam irradiation surface on the material surface is linear compared to the usual spot-like shape. etc. may be effective. In order to generate such a linear electron beam, for example, an anisotropic method that combines a rectangular cathode, a control electrode with a matching rectangular hole, and an anode with a rectangular hole similar to these rectangles is used. It is conceivable to use a magnetic electron gun. In such an electron gun, a linear electron beam is generated near the anode, that is, when the working distance is small. However, when the sample is placed far away from the anode, that is, when the working distance is large, the electron beam becomes blurred rather than linear.
Therefore, if an anisotropic electron lens is provided after the anode, that is, on the sample side, to focus the short side of the electron beam, the long side will become long, which will reduce the energy density of the beam and make the density distribution uneven. arise.

(Objective of the present invention) The present invention eliminates such conventional drawbacks, and enables the beam current density of a linear electron beam to be large and have a small distribution even for a sample placed relatively far from the electron source. The aim is to provide a uniform device.

(Structure of the Invention) According to the present invention, a rectangular cathode, a control electrode having a rectangular hole and surrounding the cathode, an anode which is at a high potential with respect to the cathode and has a circular hole through which electrons can pass, located between the anodes,
A linear electron beam heat treatment apparatus equipped with an extraction electrode having a higher potential than the anode, wherein the shape of the electron passage hole of the extraction electrode is rectangular on the side opposite to the cathode and circular on the side opposite to the anode. An electron beam heat treatment device is obtained.

(Detailed Description of Configuration) The present invention solves the problems of the prior art by adopting the above-described configuration. First, a linear electron beam with a high potential and a large beam current density is extracted using a rectangular cathode, a control electrode each having a rectangular hole, and a high potential extraction electrode. A circular hole is provided at the rear stage of the extraction electrode, and an anode having a circular hole opposing the extraction electrode constitutes an axially rotationally symmetrical electrode system, and thereafter it is easy to configure an axially rotationally symmetrical electron lens system. The linear electron beam, which has passed through the extraction electrode and has been accelerated to a high potential, is decelerated by the anode to a low, predetermined potential, so that it can be projected at a position far away from the anode with a large current density and a uniform density. There is.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings. FIG. 1 is a sectional view of the main part of an embodiment of the present invention and shows the hole shapes of each electrode, etc. In FIG. 1, a cathode 1 having a rectangular electron emitting part, a control electrode 2 having a rectangular hole that fits the electron emitting part, and an extraction electrode having a rectangular hole for passing electrons on the cathode side. A linear electron beam 4 is generated by an anisotropic three-electrode type electron beam 4 consisting of 3 and 3.
A sufficiently high potential, for example 60kV, is applied to the extraction electrode 3 relative to the cathode 1, and a large beam current, for example, is applied to the extraction electrode 3.
Draws out 100mA. A linear electron beam with a high beam current density formed near the extraction electrode 3 lowers the potential between the cathode 1 and the anode 5 to, for example, 15 kV.
After decelerating the sample 7 using the electron lens 6,
Project and irradiate onto the surface of By scanning the linear electron beam in the short side direction of the linear electron beam using a beam deflection system (not shown), a large area of the surface of the sample 7 can be heat-treated at once. Also, after shifting the linear electron beam a little in the long side direction, scanning in the short side direction as described above, and repeating the above operation in sequence, it is possible to cover the entire surface of the sample 7 using a spot beam. In comparison, heat treatment can be performed in a shorter time. In this case, instead of deflecting and scanning the electron beam, the sample 7 may be mechanically moved and heated.

The shape of the electron passage hole of the extraction electrode 3 is rectangular on the cathode side, but it is changed in the middle and is made into a circular hole on the side facing the anode 5. A linear electron beam with a high current density formed near the extraction electrode 3 can be projected onto the sample 7 in a similar manner with a high energy density.
For example, under the above conditions, a high energy density of about 40 kW/cm ² can be achieved. Further, the current density distribution in the long side direction is within 3%, and the distribution is uniform. The right side of FIG. 1 shows the hole shapes of each electrode shown on the left side of the figure, including the electron emitting part shape 11 of the cathode, the control electrode hole shape (rectangular) 12,
Hole shape (rectangular) on the side facing the cathode of the extraction electrode 13,
Hole shape (circular) on the side opposite to the anode of the extraction electrode 14;
These are the hole shape (circular) 15 of the anode, and the shape (circular) 16 of the inner diameter of the magnetic pole or electrode of the electron lens.

(Effects of the Invention) According to the linear electron beam heat treatment apparatus of the present invention, at a relatively low electron beam acceleration voltage (10 to 20 kV),
A fairly large beam current (several tens of mA or more) is applied as a sharp linear beam (for example, a beam with a cross-sectional dimension of about 0.3 mm on the short side and 5 mm on the long side) from the anode to the sample surface 60 cm away from the anode in the long side direction. can be irradiated with a uniform current density distribution.
Therefore, the efficiency of heat treatment and the handling of samples can be facilitated.

In addition, the anode facing hole 1 of the extraction electrode in FIG.
4. If the diameter dimensions of the anode 15 and the electron lens inner diameter 16 are made sufficiently large (for example, five times or more) compared to the dimensions of the passing electron beam, the projection aberration of the electron beam due to this axis-rotationally symmetric electromagnetic pole system can be reduced. The uniformity of the beam current density distribution in the long side direction is not impaired.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the main parts of an embodiment of the present invention. In the figure, 1... cathode, 2... control electrode, 3... extraction electrode, 4... linear electron beam, 5
. . . anode, 6 . . . electron lens, 7 . . . sample.

Claims (1)

[Claims] 1. A rectangular cathode, a control electrode having a rectangular hole and surrounding the cathode, an anode that is at a high potential with respect to the cathode and has a circular hole for electron passage, and located between the cathode and the anode, A linear electron beam heat treatment apparatus equipped with an extraction electrode having a higher potential than the anode, wherein the shape of the electron passage hole of the extraction electrode is rectangular on the side opposite to the cathode and circular on the side opposite to the anode. Electron beam heat treatment equipment.